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All Textbook Solutions for Chemistry & Chemical Reactivity

An aqueous solution contains 0.180 g of an unknown, nonionic solute in 50.0 g of water. The solution freezes at 0.040 C. What is the molar mass of the solute?Aluminon, an organic compound, is used as a reagent to test for the presence of the aluminum ion in aqueous solution. A solution of 2.50 g of aluminon in 50.0 g of water freezes at 0.197 C. What is the molar mass of aluminon?47PS To make homemade ice cream, you cool the milk and cream by immersing the container in ice and a concentrated solution of rock salt (NaCl) in water. If you want to have a water-salt solution that freezes at 10. C, what mass of NaCl must you add to 3.0 kg of water? (Assume the vant Hoff factor, i, for NaCl is 1.85.)List the following aqueous solutions in order of increasing melting point. (The last three are all assumed to dissociate completely into ions in water.) (a) 0.1 m sugar (b) 0.1 m NaCl (c) 0.08 m CaCl2 (d) 0.04 m Na2SO4 Arrange the following aqueous solutions in order of decreasing freezing point. (The last three are all assumed to dissociate completely into ions in water.) (a) 0.20 m ethylene glycol (nonvolatile, nonelectrolyte) (b) 0.12 m K2SO4 (c) 0.10 m MgCl2 (d) 0.12 m KBr When solutions of BaCl2 and Na2SO4 are mixed, the mixture becomes cloudy. After a few days, a white solid is observed on the bottom of the beaker with a clear liquid above it. (a) Write a balanced equation for the reaction that occurs. (b) Why is the solution cloudy at first? (c) What happens during the few days of waiting?The dispersed phase of a certain colloidal dispersion consists of spheres of diameter 1.0 102 nm. (a) What are the volume (V=43r2) and surface area (A = r2) of each sphere? (b) How many spheres are required to give a total volume of 1.0 cm3? What is the total surface area of these spheres in square meters?Phenylcarbinol is used in nasal sprays as a preservative. A solution of 0.52 g of the compound in 25.0 g of water has a melting point of 0.36 C. What is the molar mass of phenylcarbinol?(a) Which aqueous solution is expected to have the higher boiling point: 0.10 m Na2SO4 or 0.15 m sugar? (b) For which aqueous solution is the vapor pressure of water higher: 0.30 m NH4NO3 or 0.15 m Na2SO4?Arrange the following aqueous solutions in order of (i) increasing vapor pressure of water and (ii) increasing boiling point. (a) 0.35 m HOCH2CH2OH (a nonvolatile solute) (b) 0.50 m sugar (c) 0.20 m KBr (a strong electrolyte) (d) 0.20 m Na2SO4 (a strong electrolyte)56GQ Dimethylglyoxime [DMG, (CH3CNOH)2] is used as a reagent to precipitate nickel ion. Assume that 53.0 g of DMC has been dissolved in 525 g of ethanol (C2H5OH). s The red, insoluble compound formed between nickel(II)ion and dimethylglyoxime (DMG) is precipitated when DMG is added to a bask solution of Ni2+ (aq). (a) What is the mole fraction of DMG? (b) What is the molality of the solution? (c) What is the vapor pressure of the ethanol over the solution at ethanols normal boiling point of 78.4 C? (d) What is the boiling point of the solution? (DMG does not produce ions in solution.) (Kbp for ethanol = +1.22 C/m)A 10.7 m solution of NaOH has a density of 1.33 g/cm3 at 20 C. Calculate the following: (a) the mole fraction of NaOH (b) the weight percent of NaOH (c) the molarity of the solution Concentrated aqueous ammonia has a molarity of 14.8 mol/L and a density of 0.90 g/cm3. What is the molality of the solution? Calculate the mole fraction and weight percent of NH3.60GQ If you want a solution that is 0.100 m in ions, what mass of Na2SO4 must you dissolve in 125 g of water? (Assume total dissociation of the ionic solid.)Consider the following aqueous solutions: (i) 0.20 m HOCH2CH2OH (nonvolatile, nonelectrolyte); (ii) 0.10 m CaCl2 (iii) 0.12 m KBr; and (iv) 0.12 m Na2SO4. (a) Which solution has the highest boiling point? (b) Which solution has the lowest freezing point? (c) Which solution has the highest water vapor pressure?(a) Which solution is expected to have the higher boiling point: 0.20 m KBr or 0.30 m sugar? (b) Which aqueous solution has the lower freezing point: 0.12 m NH4NO3 or 0.10 m Na2CO3?The solubility of NaCl in water at 100 C is 39.1 g/100. g of water Calculate the boiling point of this solution. (Assume i = 1.85 for NaCl.)Instead of using NaCl to melt the ice on your sidewalk you decide to use CaCl2. If you add 35.0 g of CaCl2 to 150. g of water, what is the freezing point of the solution? (Assume i = 2.7 for CaCl2.)The smell of ripe raspberries is due to 4-(p-hydroxyphenyl)-2-butanone, which has the empirical formula C5H6O. To find its molecular formula, you dissolve 0.135 g in 25.0 g of chloroform, CHCl3. The boiling point of the solution is 61.82 C. What is the molecular formula of the solute?Hexachlorophene has been used in germicidal soap. What is its molar mass if 0.640 g of the compound, dissolved in 25.0 g of chloroform, produces a solution whose boiling point is 61.93 C?The solubility of ammonium formate, NH4CHO2, in 100. g of water is 102 g at 0 C and 546 g at 80 C. A solution is prepared by dissolving NH4CHO2 in 200. g of water until no more will dissolve at 80 C. The solution is then cooled to 0 C. What mass of NH4CHO2 precipitates? (Assume that no water evaporates and that the solution is not supersaturated.)How much N2 can dissolve in water at 25 C if the N2 partial pressure is 585 mm Hg?Cigars are best stored in a humidor at 18 C and 55% relative humidity. This means the pressure of water vapor should be 55% of the vapor pressure of pure water at the same temperature. The proper humidity can be maintained by placing a solution of glycerol [C3H5(OH)3] and water in the humidor. Calculate the percent by mass of glycerol that will lower the vapor pressure of water to the desired value. (The vapor pressure of glycerol is negligible.)An aqueous solution containing 10.0 g of starch per liter has an osmotic pressure of 3.8 mm Hg at 25 C. (a) What is the average molar mass of starch? (The result is an average because not all starch molecules are identical.) (b) What is the freezing point of the solution? Would it be easy to determine the molecular weight of starch by measuring the freezing point depression? (Assume that the molarity and molality are the same for this solution.)72GQ Calculate the enthalpies of solution for Li2SO4 and K2SO4. Are the solution processes exothermic or endothermic? Compare them with LiCl and KCl. What similarities or differences do you find?Water at 25 C has a density of 0.997 g/cm3. Calculate the molality and molarity of pure water at this temperature.If a volatile solute is added to a volatile solvent, both substances contribute to the vapor pressure over the solution. Assuming an ideal solution, the vapor pressure of each is given by Raoults law, and the total vapor pressure is the sum of the vapor pressures for each component. A solution, assumed to be ideal, is made from 1.0 mol of toluene (C6H5CH3) and 2.0 mol of benzene (C6H6). The vapor pressures of the pure solvents are 22 mm Hg and 75 mm Hg, respectively, at 20 C. What is the total vapor pressure of the mixture? What is the mole fraction of each component in the liquid and in the vapor?A solution is made by adding 50.0 mL of ethanol (C2H5OH, d = 0.789 g/mL) to 50.0 mL of water (d = 0.998 g/mL). What is the total vapor pressure over the solution at 20 C? (See Study Question 75.) The vapor pressure of ethanol at 20 C is 43.6 mm Hg.A 2.0% (by mass) aqueous solution of novocainium chloride (C13H21ClN2O2) freezes at 0.237 C. Calculate the vant Hoff factor, i. How many moles of ions are in the solution per mole of compound?A solution is 4.00% (by mass) maltose and 96.00% water. It freezes at 0.229 C. (a) Calculate the molar mass of maltose (which is not an ionic compound). (b) The density of the solution is 1.014 g/mL Calculate the osmotic pressure of the solution.The following table lists the concentrations of the principal ions in seawater: (a) Calculate the freezing point of seawater. (b) Calculate the osmotic pressure of seawater at 25 C. What is the minimum pressure needed to purify seawater by reverse osmosis?A tree is 10.0 m tall. (a) What must be the total molarity of the solutes if sap rises to the top of the tree by osmotic pressure at 20 C? Assume the groundwater outside the tree is pure water and that the density of the sap is 1.0 g/mL. (1 mm Hg = 13.6 mm H2O.) (b) If the only solute in the sap is sucrose, C12H22O11, what is its percent by mass?81GQ A compound is known to be a potassium halide, KX. If 4.00 g of the salt is dissolved in exactly 100 g of water, the solution freezes at 1.28 C. Identity the halide ion in this formula.85GQ If one is very careful, it is possible to float a needle on the surface of water. (If the needle is magnetized, it will turn to point north and south and become a makeshift compass.) What would happen to the needle if a drop of liquid soap is added to the solution? Explain the observation.A solution of benzoic acid in benzene has a freezing point of 3.1 C and a boiling point of 82.6 C. (The freezing point of pure benzene is 5.50 C, and its boiling point is 80.1 C) The structure of benzoic acid is Benzoic acid, C6H5CO2H What can you conclude about the state of the benzoic acid molecules at the two different temperatures? Recall the discussion of hydrogen bonding in Section 11.3.You dissolve 5.0 mg of iodine, I2, in 25 mL of water. You then add 10.0 mL of CCl4 and shake the mixture. If I2 is 85 times more soluble in CCl4 than in H2O (on a volume basis), what are the masses of I2 in the water and CCl4 layers after shaking? (Figure 13.5.)89IL In a police forensics lab, you examine a package that may contain heroin. However, you find the white powder is not pure heroin but a mixture of heroin (C12H23O5N) and lactose (C12H22O11). To determine the amount of heroin in the mixture, you dissolve 1.00 g of the white powdery mixture in water in a 100.0-mL volumetric flask. You find that the solution has an osmotic pressure of 539 mm Hg at 25 C. What is the composition of the mixture?An organic compound contains carbon (71.17%), hydrogen (5.12%) with the remainder nitrogen. Dissolving 0.177 g of the compound in 10.0 g of benzene gives a solution with a vapor pressure of 94.16 mm Hg at 25 C. (The vapor pressure of pure benzene at this temperature is 95.26 mm Hg.) What is the molecular formula for the compound?92IL When sails of Mg2+, Ca2+, and Be2+ are placed in water, the positive ion is hydrated (as is the negative ion). Which of these three cations is most strongly hydrated? Which one is least strongly hydrated?Explain why a cucumber shrivels up when it is placed in a concentrated solution of salt.95SCQ A 100.-gram sample of sodium chloride (NaCl) is added to 100. mL of water at 0 C. After equilibrium is reached, about 64 g of solid remains undissolved. Describe the equilibrium that exists in this system at the particulate level.97SCQ 98SCQ Starch contains CC, CH, CO, and OH bonds. Hydrocarbons have only CC and CH bonds. Both starch and hydrocarbons can form colloidal dispersions in water. Which dispersion is classified as hydrophobic? Which is hydrophilic? Explain briefly.100SCQ You have two aqueous solutions separated by a semipermeable membrane. One contains 5.85 g of NaCl dissolved in 100. mL of solution, and the other contains 8.88 g of KNO3 dissolved in 100. mL of solution. In which direction will solvent flow: from the NaCl solution to the KNO3 solution, or from KNO3 to NaCl? Explain briefly.102SCQ Sodium chloride (NaCl) is commonly used to melt ice on roads during the winter. Calcium chloride (CaCl2) is sometimes used for this purpose too. Let us compare the effectiveness of equal masses of these two compounds in lowering the freezing point of water, by calculating the freezing point depression of solutions containing 200. g of each salt in 1.00 kg of water. (An advantage of CaCl2 is that it acts more quickly because it is hygroscopic, that is. it absorbs moisture from the air to give a solution and begin the process. A disadvantage is that this compound is more costly.)105SCQ 106SCQ 107SCQ Sucrose decomposes to fructose and glucose in acid solution. A plot of the concentration of sucrose as a function of time is given in the margin. What is the rate of change of the sucrose concentration over the first 2 hours? What is the rate of change over the last 2 hours? Concentration versus time for the decomposition of sucrose.What are the relative rates of appearance or disappearance of each product and reactant in the decomposition of nitrosyl chloride, NOCI? 2 NOC1(g) 2 NO(g) + Cl2(g)The initial rate ( [NO]/ t] of the reaction of nitrogen monoxide and oxygen NO(g) + 2O2(g) NO2(g) was measured for various initial concentrations of NO and O2 at 25 C. Determine the rate equation from these data. What is the value of the rate constant, k, and what are its units?The rate constant, k, at 25 C is 0.27/h for the reaction Pt(NH3)2Cl2(aq) + H2O() [Pt(NH3)2(H2O)Cl]+(aq) + Cl(aq) and the rate equation is Reaction rate = k[Pt(NH3)2C12] Calculate the rate of reaction when the concentration of Pt(NH3)2Cl2 is 0.020 M.Sucrose, a sugar, decomposes in acid solution to give glucose and fructose. The reaction is first-order in sucrose, and the rate constant at 25 C is k = 0.21 h1. If the initial concentration of sucrose is 0.010 mol/L, what is its concentration after 5.0 h?Gaseous azomethane (CH3N2CH3) decomposes to ethane and nitrogen when heated: CH3N2CH3(g) CH3CH3(g) + N2(g) The decomposition of azomethane is a first-order reaction with k = 3.6 104 s1 at 600 K. (a) A sample of gaseous CH3N2CH3 is placed in a flask and heated at 600 K for 150 seconds. What fraction of the initial sample remains after this time? (b) How long must a sample be heated so that 99% of the sample has decomposed?14.7CYU The catalyzed decomposition of hydrogen peroxide is first-order in [H2O2]. It was found that the concentration of H2O2 decreased from 0.24 M to 0.060 M over a period of 282 minutes. What is the half-life of H2O2? What is the rate constant for this reaction? What is the initial rate of decomposition at the beginning of this experiment (when [H2O2] = 0.24 M)?Americium is used in smoke detectors and in medicine for the treatment of certain malignancies. One isotope of americium, 241Am, has a rate constant, k, for radioactive decay of 0.0016 y1. In contrast, radioactive iodine-125, which is used for studies of thyroid functioning, has a rate constant for decay of 0.011 d1. (a) What are the half-lives of these isotopes? (b) Which isotope decays faster? (c) If you are given a dose of iodine-125 containing 1.6 1015 atoms, how many atoms remain after 2.0 days?14.10CYU The colorless gas N2O4, decomposes to the brown gas NO2 in a first-order reaction. N2O4(g) 2 NO2(g) The rate constant k = 4.5 103 s1 at 274 K and k = 1.00 104 s1 at 283 K. What is the activation energy, Ea?Nitrogen monoxide is reduced by hydrogen to give nitrogen and water: 2 NO(g) + 2 H2(g) N2(g) + 2 H2O(g) One possible mechanism for this reaction involves the following reactions: 2 NO(g) N2O2(g) N2O2(g) + H2(g) N2O(g) + H2O(g) N2O(g) + H2(g) N2(g) + H2O(g) What is the molecularity of each of the three steps? What is the rate equation for the third step? Identify the intermediates in this reaction; how many different intermediates are there? Show that the sum of these elementary steps gives the equation for the overall reaction.14.13CYU One possible mechanism for the decomposition of nitryl chloride, NO2CI, is What is the overall reaction? What rate law would be derived from this mechanism? What effect does increasing the concentration of the product NO2 have on the reaction rate?1.1ACP 1.2ACP 2.1ACP 2.2ACP 2.3ACP Determine the activation energy for the reaction of H2 and I2 to produce HI, given the data in the table.Give the relative rates of disappearance of reactants and formation of products for each of the following reactions. (a) 2 O3(g) 3 O2(g) (b) 2 HOF(g) 2 HF(g) + O2(g)Give the relative rates of disappearance of reactants and formation of products for each of the following reactions. (a) 2 NO(g) + Br2(g) 2NOBr(g) (b) N2(g) + 3H2(g) 2NH3(g)In the reaction 2 O3(g) 3 O2(g), the rate of formation of O2 is 1.5 103 mol/L s. What is the rate of decomposition of O3?In the synthesis of ammonia, if [H2]/t = 4.5 104 mol/L min, what is [NH3]/t? N2(g) + 3 H2(g) 2 NH3(g)Experimental data are listed here for the reaction A 2 B. (a) Prepare a graph from these data; connect the points with a smooth line; and calculate the rate of change of [B] for each 10-second interval from 0.0 to 40.0 seconds. Does the rate of change decrease from one time interval to the next? Suggest a reason for this result. (b) How is the rate of change of [A] related to the rate of change of [B] in each time interval? Calculate the rate of change of [A] for the time interval from 10.0 to 20.0 seconds.Phenyl acetate, an ester, reacts with water according to the equation The data in the table were collected for this reaction at 5 C. (a) Plot the phenyl acetate concentration versus time, and describe the shape of the curve observed. (b) Calculate the rate of change of the phenyl acetate concentration during the period 15.0 seconds to 30.0 seconds and also during the period 75.0 seconds to 90.0 seconds. Why is one value smaller than the other?Using the rate equation Rate = k[A]2[B], define the order of the reaction with respect to A and B. What is the total order of the reaction?A reaction has the experimental rate equation Rate = k[A]2. How will the rate change if the concentration of A is tripled? If the concentration of A is halved?The reaction between ozone and nitrogen dioxide at 231 K is first-order in both [NO2] and [O3]. 2 NO2(g) + O3(g) N2O5(g) + O2(g) (a) Write the rate equation for the reaction. (b) If the concentration of NO2 is tripled (and [O3] is not changed), what is the change in the reaction rate? (c) What is the effect on reaction rate if the concentration of O3 is halved (with no change in [NO2])?Nitrosyl bromide, NOBr, is formed from NO and Br2: 2 NO(g) + Br2(g) 2 NOBr(g) Experiments show that this reaction is second-order in NO and first-order in Br2. (a) Write the rate equation for the reaction. (b) How does the initial reaction rate change if the concentration of Br2 is changed from 0.0022 mol/L to 0.0066 mol/L? (c) What is the change in the initial rate if the concentration of NO is changed from 0.0024 mol/L to 0.0012 mol/L?The data in the table are for the reaction of NO and O2 at 660 K. NO(g) + O2(g) NO2(g) (a) Determine the order of the reaction for each reactant. (b) Write the rate equation for the reaction. (c) Calculate the rate constant. (d) Calculate the rate (in mol/L s) at the instant when [NO] = 0.015 mol/L and [O2] = 0.0050 mol/L. (e) At the instant when NO is reacting at the rate 1.0 104 mol/L s, what is the rate at which O2 is reacting and NO2 is forming?The reaction 2 NO(g) + 2 H2(g) N2(g) + 2 H2O(g) was studied at 904 C, and the data in the table were collected. (a) Determine the order of the reaction for each reactant. (b) Write the rate equation for the reaction. (c) Calculate the rate constant for the reaction. (d) Find the rate of appearance of N2 at the instant when [NO] = 0.350 mol/L and [H] = 0.205 mol/L.Data for the reaction NO(g) + O2(g) NO2(g) are given (for a particular temperature) in the table. (a) What is the rate law for this reaction? (b) What is the rate constant for the reaction? (c) What is the initial rate of the reaction in experiment 4?Data for the following reaction are given in the table below. CO(g) + NO2(g) CO2(g) + NO(g) (a) What is the rate law for this reaction? (b) What is the rate constant for the reaction? (c) What is the initial rate of the reaction in experiment 4?The rate equation for the hydrolysis of sucrose to fructose and glucose Cl2H22O11(aq) + H2O () 2 C6Hl2O6(aq) is [sucrose]/t = k[C12H22O11]. After 27 minutes at 27 C, the sucrose concentration decreased from 0.0146 M to 0.0132 M. Find the rate constant, k.The decomposition of N2O5 in CCl4 is a first-order reaction. If 2.56 mg of N2O5 is present initially and 2.50 mg is present after 4.26 minutes at 55 C, what is the value of the rate constant, k?The decomposition of SO2Cl2 is a first-order reaction: SO2Cl2(g) SO2(g) + Cl2(g) The rate constant for the reaction is 2.8 103 min1 at 600 K. If the initial concentration of SO2Cl2 is 1.24 103 mol/L, how long will it take for the concentration to drop to 0.31 103 mol/L?The conversion of cyclopropane to propene (Example 14.5) occurs with a first-order rate constant of 2.42 102 h1. How long will it take for the concentration of cyclopropane to decrease from an initial concentration of 0.080 mol/L to 0.020 mol/L?Hydrogen peroxide, H2O2(aq), decomposes to H2O() and O2(g) in a reaction that is first-order in H2O2 and has a rate constant k = 1.06 103 min1 at a given temperature. (a) How long will it take for 15% of a sample of H2O2 to decompose? (b) How long will it take for 85% of the sample to decompose?The decomposition of nitrogen dioxide at a high temperature NO2(g) NO(g) + O2(g) is second-order in this reactant. The rate constant for this reaction is 3.40 L/mol min. Determine the time needed for the concentration of NO2 to decrease from 2.00 mol/L to 1.50 mol/L.At 573 K, gaseous NO2(g) decomposes, forming NO(g) and O2(g). If a vessel containing NO2(g) has an initial concentration of 1.9 102 mol/L, how long will it take for 75% of the NO2(g) to decompose? The decomposition of NO2(g) is second-order in the reactant and the rate constant for this reaction, at 573 K, is 1.1 L/mol s.The dimerization of butadiene, C4H6, to form 1,5-cyclooctadiene is a second-order process that occurs when the diene is heated. In an experiment, a sample of 0.0087 mol of C4H6 was heated in a 1.0-L flask. After 600. seconds, 21% of the butadiene had dimerized. Calculate the rate constant for this reaction.The decomposition of ammonia on a metal surface to form N2 and H2 is a zero-order reaction (Figure 14.7c). At 873 C, the value of the rate constant is 1.5 103 mol/L s. How long it will take to completely decompose 0.16 g of NH3 in a 1.0-L flask?Hydrogen iodide decomposes when heated, forming H2(g) and I2(g). The rate law for this reaction is [HI]/t = k[HI]2. At 443C, k = 30. L/mol min. If the initial HI(g) concentration is 1.5 102 mol/L, what concentration of HI(g) will remain after 10. minutes?The rate equation for the decomposition of N2O5 (giving NO2 and O2) is Rate = k[N2O5]. The value of k is 6.7 105 s1 for the reaction at a particular temperature. (a) Calculate the half-life of N2O5. (b) How long does it take for the N2O5 concentration to drop to one tenth of its original value?Gaseous azomethane, CH3N=NCH3, decomposes in a first-order reaction when heated: CH3N=NCH3(g) N2(g) + C2H6(g) The rate constant for this reaction at 600 K is 0.0216 min1. If the initial quantity of azomethane in the flask is 2.00 g, how much remains after 0.0500 hour? What mass of N2 is formed in this time?The decomposition of SO2Cl2 SO2Cl2(g) SO2(g) + Cl2(g) is first-order in SO2Cl2, and the reaction has a half-life of 245 minutes at 600 K. If you begin with 3.6 103 mol of SO2Cl2 in a 1.0-L flask, how long will it take for the amount of SO2Cl2 to decrease to 2.00 104 mol?The compound Xe(CF3)2 decomposes in a first-order reaction to elemental Xe with a half-life of 30. minutes. If you place 7.50 mg of Xe(CF3)2 in a flask, how long must you wait until only 0.25 mg of Xe(CF3)2 remains?The radioactive isotope 64Cu is used in the form of copper(II) acetate to study Wilsons disease. The isotope has a half-life of 12.70 hours. What fraction of radioactive copper(II) acetate remains after 64 hours?Radioactive gold-198 is used in the diagnosis of liver problems. The half-life of this isotope is 2.7 days. If you begin with a 5.6-mg sample of the isotope, how much of this sample remains after 1.0 day?31PS Ammonia decomposes when heated according to the equation NH3(g) NH2(g) + H(g) The data in the table for this reaction were collected at a high temperature. Plot In [NH3] versus time and 1/[NH3] versus time. What is the order of this reaction with respect to NH3? Find the rate constant for the reaction from the slope.Gaseous NO2 decomposes at 573 K. NO2(g) NO(g) + O2(g) The concentration of NO2 was measured as a function of time. A graph of 1/[NO2] versus time gives a straight line with a slope of 1.1 L/mol s. What is the rate law for this reaction? What is the rate constant?The decomposition of HOF occurs at 25 C. HOF(g) HF(g) + O2(g) Using the data in the table below, determine the rate law, and then calculate the rate constant.35PS 36PS Calculate the activation energy, Ea, for the reaction 2 N2O5(g) 4 NO2(g) + O2(g) from the observed rate constants: k at 25 C = 3.46 105 s1 and k at 55 C = 1.5 103 s1.If the rate constant for a reaction triples when the temperature rises from 3.00 102 K to 3.10 102 K, what is the activation energy of the reaction?When healed lo a high temperature, cyclobutane, C4H8 decomposes to ethylene: C4H8(g) 2 C2H4(g) The activation energy, Ea, for this reaction is 260 kJ/mol. At 800 K, the rate constant k = 0.0315 s1. Determine the value of k at 850 K.When heated, cyclopropane is converted to propene (Example 14.5) Rate constants for this reaction at 470 C and 510 C are k = 1.10 104 s1 and k = 1.02 103 s1, respectively. Determine the activation energy, Ea, from these data.The reaction of H2 molecules with F atoms H2(g) + F(g) HF(g) + H(g) has an activation energy of 8 kJ/mol and an enthalpy change of 133 kJ/mol. Draw a diagram similar to Figure 14.11 for this process. Indicate the activation energy and enthalpy change on this diagram.42PS Compare the lock-and-key and induced-fit models for substrate binding to an enzyme.44PS 45PS The enzyme carbonic anhydrase catalyzes the transformation of carbon dioxide into hydrogen carbonate ions. This reaction was studied by H. DeVoe and G. B. Kistiakowsky (Journal of the American Chemical Society, Vol. 83, p. 274, 1961) and found to obey the Michaelis-Menten model. Use the data below at a given temperature to calculate the maximum rate of the reaction. Ratemax. See Question 45 for the graphical method to use.What is the rate law for each of the following elementary reactions? (a) NO(g) + NO3(g) 2 NO2(g) (b) Cl(g) + H2(g) HCl(g) + H(g) (c) (CH3)3CBr(aq) (CH3)3C+(aq) + Br(aq)What is the rate law for each of the following elementary reactions? (a) Cl(g) + ICl(g) I(g) + Cl2(g) (b) O(g) + O3(g) 2 O2(g) (c) 2 NO2(g) N2O4(g)Ozone, O3, in the Earths upper atmosphere decomposes according to the equation 2 O3(g) 3 O2(g) The mechanism of the reaction is thought to proceed through an initial fast, reversible step followed by a slow, second step. Step 1: Fast, reversible O3(g) O2(g) + O(g) Step 2: Slow O3(g) + O(g) 2 O2(g) (a) Which of the steps is rate-determining? (b) Write the rate equation for the rate-determining step The reaction of NO2(g) and CO(g) is thought to occur in two steps to give NO and CO2: Step 1: Slow NO2(g) + NO2(g) NO(g) + NO3(g) Step 2: Fast NO3(g) + CO(g) NO2(g) + CO2(g) (a) Show that the elementary steps add up to give the overall, stoichiometric equation. (b) What is the molecularity of each step? (c) For this mechanism to be consistent with kinetic data, what must be the experimental rate equation? (d) Identify any intermediates in tins reaction.A proposed mechanism for the reaction of NO2 and CO is Step 1: Slow, endothermic 2 NO2(g) NO(g) + NO3(g) Step 2: Fast, exothermic NO3(g) + CO(g) NO2(g) + CO2(g) Overall Reaction: Exothermic NO2(g) + CO(g) NO(g) + CO2(g) (a) Identify each of the following as a reactant, product, or intermediate: NO2(g), CO(g), NO3(g), CO2(g), NO(g). (b) Draw a reaction coordinate diagram for this reaction. Indicate on this drawing the activation energy for each step and the overall enthalpy change.The mechanism for the reaction of CH3OH and HBr is believed to involve two steps. The overall reaction is exothermic. Step 1: Fast, endothermic CH3OH + H+ CH3OH2+ Step 2: Slow CH3OH2+ + Br CH3Br + H2O (a) Write an equation for the overall reaction. (b) Draw a reaction coordinate diagram for this reaction. (c) Show that the rate law for this reaction is Rate = k[CH3OH][H+][Br].A reaction has the following experimental rate equation: Rate = k[A]2[B]. If the concentration of A is doubled and the concentration of B is halved, what happens to the reaction rate?For a first-order reaction, what fraction of reactant remains after five half-lives have elapsed?55GQ Data for the following reaction are given in the table. 2 NO(g) + Br2(g) 2 NOBr(g) What is the order of the reaction with respect to [NO] and [Br2], and what is the overall order of the reaction?Formic acid decomposes at 550 C according to the equation HCO2H(g) CO2(g) + H2(g) The reaction follows first-order kinetics. In an experiment, it is determined that 75% of a sample of HCO2H has decomposed in 72 seconds. Determine t, for this reaction.Isomerization of CH3NC occurs slowly when CH3NC is heated. CH3NC(g) CH3CN(g) To study the rate of this reaction at 488 K, data on [CH3NC] were collected at various times. Analysis led to the following graph. (a) What is the rate law for this reaction? (b) What is the equation for the straight line in this graph? (c) Calculate the rate constant for this reaction. (d) How long does it take for half of the sample to isomerize? (e) What is the concentration of CH3NC after 1.0 104 s?When heated, tetrafluoroethylene dimerizes to form octafluorocyclobutane. C2F4(g) C4F8(g) To determine the rate of this reaction at 488 K, the data in the table were collected. Analysis was done graphically, as shown below: (a) What is the rate law for this reaction? (b) What is the value of the rate constant? (c) What is the concentration of C2F4 after 600 s? (d) How long will it take until the reaction is 90% complete?Data in the table were collected at 540 K for the following reaction: CO(g) + NO2(g) CO2(g) + NO(g) Using the data in the table: (a) Determine the reaction order with respect to each reactant. (b) Derive the rate equation. (c) Calculate the rate constant, giving the correct units for k.Ammonium cyanate, NH4NCO, rearranges in water to give urea, (NH2)2CO. NH4NCO(aq) (NH2)2CO(aq) Using the data in the table: (a) Decide whether the reaction is first-order or second-order. (b) Calculate k for this reaction. (c) Calculate the half-life of ammonium cyanate under these conditions. (d) Calculate the concentration of NH4NCO after 12.0 hours.62GQ At temperatures below 500 K, the reaction between carbon monoxide and nitrogen dioxide CO(g) + NO2(g) CO2(g) + NO(g) has the following rate equation: Rate k[NO2]2. Which of the three mechanisms suggested here best agrees with the experimentally observed rate equation? Mechanism1Single,elementarystepNO2+COCO2+NOMechanism2TwostepsSlowNO2+NO2NO3+NOFastNO3+CONO2+CO2Mechanism3TwostepsSlowNO2NO+OFastCO+OCO2 Nitryl fluoride can be made by treating nitrogen dioxide with fluorine: 2 NO2(g) + F2(g) 2 NO2F(g) Use the rate data in the table to do the following: (a) Write the rate equation for the reaction. (b) Indicate the order of reaction with respect to each component of the reaction. (c) Find the numerical value of the rate constant, k.The decomposition of dinitrogen pentaoxide N2O5(g) 2 NO2(g) + O2(g) has the following rate equation: Rate = k[N2O5]. It has been found experimentally that the decomposition is 20.5% complete in 13.0 hours at 298 K. Calculate the rate constant and the half-life at 298 K.The data in the table give the temperature dependence of the rate constant for the reaction N2O5(g) 2 NO2(g) + O2(g). Plot these data in the appropriate way to derive the activation energy for the reaction.The decomposition of gaseous dimethyl ether at ordinary pressures is first-order. Its half-life is 25.0 minutes at 500 C: CH3OCH3(g) CH4(g) + CO(g) + H2(g) (a) Starting with 8.00 g of dimethyl ether, what mass remains (in grams) after 125 minutes and after 145 minutes? (b) Calculate the time in minutes required to decrease 7.60 ng (nanograms) to 2.25 ng. (c) What fraction of the original dimethyl ether remains after 150 minutes?The decomposition of phosphine, PH3, proceeds according to the equation PH3(g)14P4(g)+32H2(g) It is found that the reaction has the following rate equation: Rate = k[PH3]. The half-life of PH3 is 37.9 seconds at 120 C. (a) How much time is required for three fourths of the PH3 to decompose? (b) What fraction of the original sample of PH3 remains after 1.00 minute?The thermal decomposition of diacetylene, C4H2, was studied at 950 C. Use the following data (K. C. Hou and H. B. Palmer, Journal of Physical Chemistry. Vol. 60, p. 858, 1965) to determine the order of the reaction.70GQ The ozone in the Earths ozone layer decomposes according to the equation 2 O3(g) 3 O2(g) The mechanism of the reaction is thought to proceed through an initial fast equilibrium and a slow step: Show that the mechanism agrees with this experimental rate law: Rate = (1/2)[O3]/t = k[O3]2[O2].Hundreds of different reactions occur in the stratosphere, among them reactions that destroy the Earths ozone layer. The table below lists several (second-order) reactions of Cl atoms with ozone and organic compounds; each is given with its rate constant. For equal concentrations of Cl and the other reactant, which is the slowest reaction? Which is the fastest reaction?Data for the reaction [Mn(CO)5(CH3CN)]+ + NC5H5 (Mn(CO)5(NC5H5)]+ + CH3CN are given in the table. Calculate Ea from a plot of In k versus 1/T.The gas-phase reaction 2 N2O5(g) 4 NO2(g) + O2(g) has an activation energy of 103 kJ/mol, and the rate constant is 0.0900 min1at 328.0 K. Find the rate constant at 318.0 K.75GQ The decomposition of SO2Cl2 to SO2 and Cl2 is first-order in SO2Cl2. SO2Cl2(g) SO2(g) + Cl2(g) Rate = k[SO2Cl2] where k = 0.17/hr (a) What is the rate of decomposition when [SO2Cl2] = 0.010 M? (b) What is the half-life of the reaction? (c) If the initial pressure of SO2Cl2 in a flask is 0.050 atm, what is the pressure of all gases (i.e., the total pressure) in the flask after the reaction has proceeded for one half-life?The decomposition of nitrogen dioxide at a high temperature NO2(g) NO(g) + O2(g) is second-order in this reactant. (a) Determine the rate constant for this reaction if it takes 1.76 min for the concentration of NO2 to fall from 0.250 mol/L to 0.100 mol/L (b) If the chemical equation is written as 2 NO2(g) 2 NO(g) + O2(g) what is the value of the rate constant?78GQ Egg protein albumin is precipitated when an egg is cooked in boiling (100 C) water. Ea for this first-order reaction is 52.0 kJ/mol. Estimate the time to prepare a 3-minute egg at an altitude at which water boils at 90 C.A The compound 1,3-butadiene (C4H6) forms 1,5-cyclooctadiene, C8H12 at higher temperatures. C4H6(g) C8H12(g) Use the following data to determine the order of the reaction and the rate constant, k. (Note that the total pressure is the pressure of the unreacted C4H6 at any time plus the pressure of the C8H12.)Hypofluorous acid, HOF, is very unstable, decomposing in a first-order reaction to give HF and O2, with a half-life of 30. minutes at room temperature: HOF(g) HF(g) + O2(g) If the partial pressure of HOF in a 1.00-L flask is initially 1.00 102 mm Hg at 25 C, what are the total pressure in the flask and the partial pressure of HOF after exactly 30 minutes? After 45 minutes?We know that the decomposition of SO2Cl2 is first-order in SO2Cl2, SO2Cl2 SO2(g) + Cl2(g) with a half-life of 245 minutes at 600 K. If you begin with a partial pressure of SO2Cl2 of 25 mm Hg in a 1.0-L flask what is the partial pressure of each reactant and product after 245 minutes? What is the partial pressure of each reactant and product after 12 hours?Nitramide, NO2NH2, decomposes slowly in aqueous solution according to the following reaction: NO2NH2(aq) N2O(g) + H2O() The reaction follows the experimental rate law Rate=k[NO2NH2][H3O+] (a) What is the apparent order of the reaction in a pH buffered solution? (In a pH buffered solution, the concentration of H3O+ is a constant.) (b) Which of the following mechanisms is the most appropriate for the interpretation of this rate law? Explain. (Note that when writing the expression for K, the equilibrium constant, [H2O] is not involved. See Chapter 15.) Mechanism 1 NO2NH2K1N2O+H2O Mechanism 2 NO2NH2+H3O+k2k2NO2NH3++H2O(rapidequilibrium) NO2NH3+k3N2O+H3O+(rate-limitingstep) Mechanism 3 NO2NH2+H2Ok4k4NO2NH+H3O+(rapidequilibrium)NO2NHk5N2O+OH(rate-limitingstep)H3O++OHk62H2O(veryfastreaction) (c) Show the relationship between the experimentally observed rate constant, k, and the rate constants in the selected mechanism. (d) Based on the experimental rate law, will the reaction rate increase or decrease if the pH of the solution is increased?84GQ The color change accompanying the reaction of phenolphthalein with strong base is illustrated below. The change in concentration of the dye can be followed by spectrophotometry (Section 4.9), and some data collected by that approach are given below. The initial concentrations were [phenolphthalein] = 0.0050 mol/L and [OH] = 0.61 mol/L. (Data are taken from review materials for kinetics at chemed.chem.purdue.edu.) (For more details on this reaction see L Nicholson, Journal of Chemical Education, Vol. 66, p. 725, 1989.) (a) Plot the data above as [phenolphthalein] versus time, and determine the average rate from t = 0 to t = 15 seconds and from t = 100 seconds to t = 125 seconds. Does the rate change? If so, why? (b) Use a graphical method to determine the order of the reaction with respect to phenolphthalein. Write the rate law, and determine the rate constant. (c) What is the half-life for the reaction?87IL 88IL The oxidation of iodide ion by the hypochlorite ion in the presence of hydroxide ions I(aq) + ClO(aq) IO(aq) + Cl(aq) was studied at 25 C, and the following initial rates data (Y. Chia and R. E. Connick, Journal of Physical Chemistry, Vol. 63, p. 1518, 1959) were collected: (a) Determine the rate law for this reaction. (b) One mechanism that has been proposed for this reaction is the following: Show that the rate law predicted by this mechanism matches the experimentally determined rate law in part a. (Note that when writing the expression for K the equilibrium constant, [H2O] is not involved. See Chapter 15.)The acid-catalyzed iodination of acetone CH3COCH3(aq) + I2(aq) CH3COCH2I(aq) + HI(aq) is a common laboratory experiment used in general chemistry courses to teach the method of initial rates. The reaction is followed spectrophotometrically by the disappearance of the color of iodine in the solution. The following data (J. P. Birk and D. L Walters, Journal of Chemical Education, Vol. 69, p. 585, 1992) were collected at 23 C for this reaction. Determine the rate law for this reaction.91SCQ The following statements relate to the reaction for the formation of HI: H2(g) + I2(g) 2 HI(g)Rate = k[H2][I2] Determine which of the following statements are true. If a statement is false, indicate why it is incorrect. (a) The reaction must occur in a single step. (b) This is a second-order reaction overall. (c) Raising the temperature will cause the value of k to decrease. (d) Raising the temperature lowers the activation energy for this reaction. (e) If the concentrations of both reactants are doubled, the rate will double. (f) Adding a catalyst in the reaction will cause the initial rate to increase.Chlorine atoms contribute to the destruction of the Earths ozone layer by the following sequence of reactions: Cl + O3 ClO + O2 ClO + O Cl + O2 where the O atoms in the second step come from the decomposition of ozone by sunlight: O3(g) O(g) + O2(g) What is the net equation on summing these three equations? Why does this lead to ozone loss in the stratosphere? What is the role played by Cl in this sequence of reactions? What name is given to species such as ClO?95SCQ 96SCQ The reaction cyclopropane propene occurs on a platinum metal surface at 200 C. (The platinum is a catalyst.) The reaction is first-order in cyclopropane. Indicate how the following quantities change (increase, decrease, or no change) as this reaction progresses, assuming constant temperature. (a) [cyclopropane] (b) [propene] (c) [catalyst] (d) the rate constant, k (e) the order of the reaction (f) the half-life of cyclopropane 98SCQ Examine the reaction coordinate diagram given here. (a) How many steps are in the mechanism for the reaction described by this diagram? (b) Is the reaction overall exothermic or endothermic?Draw a reaction coordinate diagram for an exothermic reaction that occurs in a single step. Identify the activation energy and the net energy change for the reaction on this diagram. Draw a second diagram that represents the same reaction in the presence of a catalyst, assuming a single-step reaction is involved here also. Identify the activation energy of this reaction and the energy change. Is the activation energy in the two drawings different? Does the energy evolved in the two reactions differ?Consider the reaction of ozone and nitrogen monoxide to form nitrogen dioxide and oxygen. O3(g) + NO(g) NO2(g) + O2(g) Which of the following orientations for the collision between ozone and nitrogen monoxide could perhaps lead to an effective collision between the molecules? (a) (b) (c) (d)Write the equilibrium constant expression for each of the following reactions in terms of concentrations. (a) CO2(g) + C(s) 2 CO(g) (b) [Cu(NH3)4)2+(aq) Cu2+(aq) + 4 NH3(aq) (c) CH3CO2H(aq) + H2O() CH3CO2(aq) + H3O+(aq)Answer the following questions regarding the butane isobutane equilibrium (Kc = 2.50 at 298 K). (a) Is the system at equilibrium when [butane] = 0.00097 M and [isobutane] = 0.00218 M? If not, in which direction will the reaction proceed to achieve equilibrium? (b) Is the system at equilibrium when[butane] = 0.00075 M and [isobutane] = 0.00260M? If not, in which direction will the reaction proceed to achieve equilibrium?A solution is prepared by dissolving 0.050 mol of diiodocyclohexane, C5H10I2, in the solvent CCl4.The total solution volume is 1.00 L When the reaction C6H10I2 C6H10 + I2 has come to equilibrium at 35 C, the concentration of I2 is 0.035 mol/L. (a) What are the concentrations of C6H10I2 and C6H10 at equilibrium? (b) Calculate Kc, the equilibrium constant.At some temperature. Kc = 33 for the reaction H2(g) + I2(g) 2 HI(g) Assume the initial concentrations of both H2 and I2 are 6.00 103 mol/L. Find the concentration of each reactant and product at equilibrium.The decomposition of PCl5(g) to form PCl3(g) and Cl2(g) has Kc = 33.3 at a high temperature. If the initial concentration of PCl5 is 0.1000 M, what are the equilibrium concentrations of the reactants and products?The conversion of oxygen to ozone has a very small equilibrium constant. 3/2 O2(g) O3(g) K = 2.5 1029 (a) What is the value of K when the equation is written using whole-number coefficients? 3 O2(g) 2 O3(g) (b) What is the value of K for the conversion of ozone to oxygen? 2 O3(g) 3 O2(g)Equilibrium exists between butane and isobutane when [butane] = 0.020 M and [isobutane] = 0.050 M. An additional 0.0200 mol/L of isobutane is added to the mixture. What are the concentrations of butane and isobutane after equilibrium has again been attained?Anhydrous ammonia is used directly as a fertilizer, but much of it is also converted to other fertilizers such as ammonium nitrate and urea. a. Write a balanced equation for the conversion of ammonia to ammonium nitrate. b. Urea is formed in the reaction of ammonia and CO2. 2 NH3(g) + CO2(g) (NH2)2CO(s) + H2O(g) Would high pressure favor urea production? Would high temperature? fH for solid urea = 333.1 kJ/mol-rxn). Explain your answers.1.2ACP Freezing point depression is one means of determining the molar mass of a compound. The freezing point depression constant of benzene is 5.12 C/m. a. When a 0.503 g sample of the white crystalline dimer is dissolved in 10.0 g benzene, the freezing point of benzene is decreased by 0542 C. Verify that the molar mass of the dimer is 475 g/mol when determined by freezing point depression. Assume no dissociation of the dimer occurs. b. The correct molar mass of the dimer is 487 g/mol. Explain why the dissociation equilibrium causes the freezing point depression calculation to yield a lower molar mass for the dimer.2.2ACP A 0.64 g sample of the white crystalline dimer (4) is dissolved in 25.0 mL of benzene at 20 C. Use the equilibrium constant to calculate the concentrations of monomer (2) and dimer (4) in this solution.Predict whether the dissociation of the dimer to the monomer is exothermic or endothermic, based on the tact that at higher temperatures the yellow color of the solution intensifies.2.5ACP Write equilibrium constant expressions for the following reactions. For gases, use either pressures or concentrations. (a) 2 H2O2(g) 2 H2O(g) + O2(g) (b) CO(g) + O2g CO2(g) (c) C(s) + CO2(g) 2 CO(g) (d) NiO(s) + CO(g) Ni(s) + CO2(g)Write equilibrium constant expressions for the following reactions. For gases, use either pressures or concentrations. (a) 3 O2(g) 2 O3(g) (b) Fe(s) + 5 CO(g) Fe(CO)5(g) (c) (NH4)2CO3(s) 2 NH3(g) + CO2(g) + H2O(g) (d) Ag2SO4(s) 2 Ag+(aq) + SO42(aq)Kc = 5.6 1012 at 500 K for the dissociation of iodine molecules to iodine atoms. I2(g) 2 I(g) A mixture has [I2] = 0.020 mol/Land [I] = 2.0 108 mol/L. Is the reaction at equilibrium (at 500 K)? If not, which way must the reaction proceed to reach equilibrium?The reaction 2 NO2(g) N2O4(g) has an equilibrium constant, Kc, of 170 at 25 C. If 2.0 103 mol of NO2 is present in a 10.-L. Flask along with 1.5 103 mol of N2O4, is the system at equilibrium? If it is not at equilibrium, does the concentration of NO2 increase or decrease as the system proceeds to equilibrium?A mixture of SO2, O2, and SO3 at 1000 K contains the gases at the following concentrations: [SO2] = 5.0 103 mol/L, [O2] = 1.9 103 mol/L, and [SO3] = 6.9 103 mol/L. Is the reaction at equilibrium? If not, which way will the reaction proceed to reach equilibrium? 2 SO2(g) + O2(g) 2 SO3(g) Kc = 279 The equilibrium constant Kc, for the reaction 2 NOCI(g) 2 NO(g) + Cl2(g) is 3.9 103 at 300 C. A mixture contains the gases at the following concentrations: [NOCl] = 5.0 103 mol/L, [NO] = 2.5 103 mol/L, and [Cl2] = 2.0 103 mol/L. Is the reaction at equilibrium at 300 C? If not, in which direction does the reaction proceed to come to equilibrium?The reaction PCl5(g) PCl3(g) + Cl2(g) was examined at 250 C. At equilibrium, [PCl5] = 4.2 105 mol/L, [PCl3] = 1.3 102 mol/L, and [Cl2] = 3.9 103 mol/L. Calculate Kc, for the reaction.An equilibrium mixture of SO2, O2, and SO3 at a high temperature contains the gases at the following concentrations: |SO2| = 3.77 103 mol/L, [O2] = 4.30 103 mol/L, and [SO3] = 4.13 103 mol/L. Calculate the equilibrium constant, Kc, for the reaction. 2 SO2(g) + O2(g) 2 SO3(g)The reaction C(s) + CO2(g) 2 CO(g) occurs at high temperatures. At 700 C, a 200.0-L tank contains 1.0 mol of CO, 0.20 mol of CO2, and 0.40 mol of C at equilibrium. (a) Calculate Kc for the reaction at 700 C. (b) Calculate Kc for the reaction, also at 700 C, if the amounts at equilibrium in the 200.0-L tank are 1.0 mol of CO, 0.20 mol of CO2, and 0.80 mol of C. (c) Compare the results of (a) and (b). Does the quantity of carbon affect the value of Kc? Explain.Hydrogen and carbon dioxide react at a high temperature to give water and carbon monoxide. H2(g) + CO2(g) H2O(g) + CO(g) (a) Laboratory measurements at 986 C show that there are 0.11 mol each of CO and H2O vapor and 0.087 mol each of H2 and CO2 at equilibrium in a 50.0-L container. Calculate the equilibrium constant for the reaction at 986 C. (b) Suppose 0.010 mol each of H2 and CO2 are placed in a 200.0-L container. When equilibrium is achieved at 986 C, what amounts of CO(g) and H2O(g), in moles, would be present? [Use the value of Kc from part (a).]A mixture of CO and Cl2 is placed in a reaction flask: [CO] = 0.0102 mol/L and [Cl2] = 0.00609 mol/L. When the reaction CO(g) + Cl2(g) COCl2(g) has come to equilibrium at 600 K, [Cl2] = 0.00301 mol/L. (a) Calculate the concentrations of CO and COCl2 at equilibrium. (b) Calculate KC.You place 0.0300 mol of pure SO3 in an 8.00-L flask at 1150 K. At equilibrium, 0.0058 mol of O2 has been formed. Calculate Kc for the reaction at 1150 K. 2 SO3(g) 2 SO2(g) + O2(g)The value of Kc for the interconversion of butane and isobutane is 2.5 at 25 C. If you place 0.017 mol of butane in a 0.50-L flask at 25 C and allow equilibrium to be established, what will be the equilibrium concentrations of the two forms of butane?Cyclohexane, C6H12, a hydrocarbon, can isomerize or change into methylcyclopentane, a compound of the same formula (C5H9CH3) but with a different molecular structure. sssss The equilibrium constant has been estimated to be 0.12 at 25 C. If you had originally placed 0.045 mol of cyclohexane in a 2.8-L flask, what would be the concentrations of cyclohexane and methylcyclopentane when equilibrium is established?The equilibrium constant for the dissociation of iodine molecules to iodine atoms I2(g) 2 I(g) is 3.76 103 at 1000 K. Suppose 0.105 mol of I2 is placed in a 12.3-L flask at 1000 K. What are the concentrations of I2 and I when the system comes to equilibrium?The equilibrium constant, Kc, for the reaction N2O4(g) 2 NO2(g) at 25 C is 5.9 103. Suppose 15.6 g of N2O4 placed in a 5.000-L flask at 25 C. Calculate the following; (a) the amount of NO2 (mol) present at equilibrium; (b) the percentage of the original N2O4 that is dissociated.Carbonyl bromide decomposes to carbon monoxide and bromine. COBr2(g) CO(g) + Br2(g) Kc is 0.190 at 73 C. If you place 0.0500 mol of COBr2 in a 2.00-L flask and heat it to 73 C, what are the equilibrium concentrations of COBr2, CO, and Br2? What percentage of the original COBr2 decomposed at this temperature?Iodine dissolves in water, but its solubility in a nonpolar solvent such as CCl4 is greater. Extracting iodine (I2) from water with the nonpolar solvent CCl4. I2 is more soluble in CCl4 and, after shaking a mixture of water and CCl4, the I2 has accumulated in the more dense CCl4 layer. The equilibrium constant is 85.0 for the process I2(aq) I2(CCl4) You place 0.0340 g of I2 in 100.0 mL of water. After shaking it with 10.0 mL of CCl4, how much I2 remains in the water layer?Which of the following correctly relates the equilibrium constants for the two reactions shown? A+B2CK12A+2B4CK2 (a) K2 = 2K1 (b) K2 = K12 (c) K2 = 1/K1 (d) K2 = l/K12 Which of the following correctly relates the equilibrium constants for the two reactions shown? A+B2CK1C12A+12BK2 (a) K2 = 1/(K1)1/2 (b) K2 = 1/K1 (c) K2 = K12 (d) K2 = K11/2 Consider the following equilibria involving SO2(g) and their corresponding equilibrium constants. SO2(g)+O2(g)SO3(g)K12SO3(g)2SO2(g)+O2(g)K2 Which of the following expressions relates K1 to K2? (a) K2 = K12 (b) K22 = K1 (c) K2 = K1 (d) K2 = 1/K1 (e) K2 = 1/K12 The equilibrium constant K for the reaction CO2(g) CO(g) + O2(g) is 6.66 1012 at 1000 K. Calculate K for the reaction 2 CO(g) + O2(g) 2 CO2(g)Calculate K for the reaction SnO2(s) + 2 CO(g) Sn(s) + 2 CO2(g) given the following information: SnO2(s)+2H2(g)Sn(s)+2H2O(g)K=8.12H2(g)+CO2(g)H2O(g)+CO(g)K=0.771 Calculate K for the reaction Fe(s) + H2O(g) FeO(s) + H2(g) given the following information: H2O(g)+CO(g)H2(g)+CO2(g)K=1.6FeO(s)+CO(g)Fe(s)+CO2(g)K=0.67 Relationship of Kc and Kp: (a) Kp for the following reaction is 0.16 at 25 C. What is the value of Kc? 2 NOBr(g) 2 NO(g) + Br2(g) (b) The equilibrium constant, Kc, for the following reaction is 1.05 at 350 K. What is the value of Kp? 2 CH2Cl2(g) CH4(g) + CCl4(g)Relationship of Kc and Kp: (a) The equilibrium constant, Kc, for the following reaction at 25 C is 170. What is the value of Kp? N2O4(g) 2 NO2(g) (b) Kc for the decomposition of ammonium hydrogen sulfide is 1.8 104 at 25 C. What is the value of Kp? NH4HS(s) NH3(g) + H2S(g)Dinitrogen trioxide decomposes to NO and NO2, in an endothermic process (rH = 40.5 kJ/mol-rxn). N2O3(g) NO(g) + NO2(g) Predict the effect of the following changes on the position of the equilibrium; that is, state which way the equilibrium will shift (left, right, or no change) when each of the following changes is made. (a) adding more N2O3(g) (b) adding more NO2(g) (c) increasing the volume of the reaction flask (d) lowering the temperature Kp for the following reaction is 0.16 at 25 C: 2 NOBr(g) 2 NO(g) + Br2(g) The enthalpy change for the reaction at standard conditions is + 16.3 kJ/mol-rxn. Predict the effect of the following changes on the position of the equilibrium; that is, state which way the equilibrium will shift (left, right, or no change) when each of the following changes is made. (a) adding more Br2(g) (b) removing some NOBr(g) (c) decreasing the temperature (d) increasing the container volume Consider the isomerization of butane with an equilibrium constant of K = 2.5. (See Study Question 13.) The system is originally at equilibrium with [butane] = 1.0 M and [isobutane] = 2.5 M. (a) If 0.50 mol/L of isobutane is suddenly added and the system shifts to a new equilibrium position, what is the equilibrium concentration of each gas? (b) If 0.50 mol/L of butane is added to the original equilibrium mixture and the system shifts to a new equilibrium position, what is the equilibrium concentration of each gas?The decomposition of NH4HS NH4HS(s) NH3(g) + H2S(g) is an endothermic process. Using Le Chateliers principle, explain how increasing the temperature would affect the equilibrium. If more NH4HS is added to a flask in which this equilibrium exists, how is the equilibrium affected? What if some additional NH3 is placed in the flask? What will happen to the pressure of NH3 if some H2S is removed from the flask?Suppose 0.086 mol of Br2 is placed in a 1.26-L flask and heated to 1756 K, a temperature at which the halogen dissociates to atoms. Br2(g) 2 Br(g) If Br2 is 3.7% dissociated at this temperature, calculate Kc.The equilibrium constant for the reaction N2(g) + O2(g) 2 NO(g) is 1.7 103 at 2300 K. (a) What is K for the reaction when written as follows? N2(g) + O2(g) NO(g) (b) What is K for the following reaction? 2 NO(g) N2(g) + O2(g)Kp for the formation of phosgene, COCl2, is 6.5 1011 at 25 C. CO(g) + Cl2(g) COCl2(g) What is the value of Kp for the dissociation of phosgene? COCl2(g) CO(g) + Cl2(g)The equilibrium constant, Kc, for the following reaction is 1.05 at 350 K. 2 CH2Cl2(g) CH4(g) + CCl4(g) If an equilibrium mixture of the three gases at 350 K contains 0.0206 M CH2Cl2(g) and 0.0163 M CH4, what is the equilibrium concentration of CCl4?Carbon tetrachloride can be produced by the following reaction: CS2(g) + 3 Cl2(g) S2Cl2(g) + CCl4(g) Suppose 0.12 mol of CS2 and 0.36 mol of Cl2 are placed in a 10.0-L flask. After equilibrium has been achieved, the mixture contains 0.090 mol CCl4. Calculate Kc.Equal numbers of moles of H2 gas and I2 vapor are mixed in a flask and heated to 700 C. The initial concentration of each gas is 0.0088 mol/L, and 78.6% of the I2 is consumed when equilibrium is achieved according to the equation H2(g) + I2(g) 2 HI(g) Calculate Kc for this reaction.The equilibrium constant for the butane isobutane isomerization reaction is 2.5 at 25 C. If 1.75 mol of butane and 1.25 mol of isobutane are mixed, is the system at equilibrium? If not, when it proceeds to equilibrium, which reagent increases in concentration? Calculate the concentrations of the two compounds when the system reaches equilibrium.At 2300 K the equilibrium constant for the formation of NO(g) is 1.7 103. N2(g) + O2(g) 2 NO(g) (a) Analysis shows that the concentrations of N2 and O2 are both 0.25 M, and that of NO is 0.0042 M under certain conditions. Is the system at equilibrium? (b) If the system is not at equilibrium, in which direction does the reaction proceed? (c) When the system is at equilibrium, what are the equilibrium concentrations?Which of the following correctly relates the two equilibrium constants for the two reactions shown? NOCl(g) NO(g) + Cl2(g)K1 2 NO(g) + Cl2(g) 2 NOCI(g)K2 (a) K2 = K12 (b) K2 = 1/(K1)1/2 (c) K2 = 1/K12 (d) K2 = 2K1 Consider the following equilibrium: COBr2(g) CO(g) + Br2(g)Kc = 0.190 at 73 C (a) A 0.50 mol sample of COBr2 is transferred to a 9.50-L flask and heated until equilibrium is attained. Calculate the equilibrium concentrations of each species. (b) The volume of the container is decreased to 4.5 L and the system allowed to return to equilibrium. Calculate the new equilibrium concentrations. (Hint: The calculation will be easier if you view this as a new problem with 0.5 mol of COBr2 transferred to a 4.5-L flask.) (c) What is the effect of decreasing the container volume from 9.50 L to 4.50 L?Heating a metal carbonate leads to decomposition. BaCO3(s) BaO(s) + CO2(g) Predict the effect on the equilibrium of each change listed below. Answer by choosing (i) no change, (ii) shifts left or (iii) shifts right. (a) add BaCO3 (b) add CO2 (c) add BaO (d) raise the temperature (e) increase the volume of the flask containing the reaction Phosphorus pentachloride decomposes at elevated temperatures. PCl5(g) PCl3(g) + Cl2(g) An equilibrium mixture at some temperature consists of 3.120 g of PCl5, 3.845 g of PCl3, and 1.787 g of Cl2 in a 10.0-L flask. If you add 1.418 g of Cl2, how will the equilibrium be affected? What will the concentrations of PCl5, PCl3, and Cl2 be when equilibrium is reestablished?Ammonium hydrogen sulfide decomposes on heating. NH4HS(s) NH3(g) + H2S(g) If Kp for this reaction is 0.11 at 25 C (when the partial pressures are measured in atmospheres), what is the total pressure in the flask at equilibrium?Ammonium iodide dissociates reversibly to ammonia and hydrogen iodide if the salt is heated to a sufficiently high temperature. NH4I(s) NH3(g) + HI(g) Some ammonium iodide is placed in a flask, which is then heated to 400 C. If the total pressure in the flask when equilibrium has been achieved is 705 mm Hg, what is the value of Kp (when partial pressures are in atmospheres)?When solid ammonium carbamate sublimes, it dissociates completely into ammonia and carbon dioxide according to the following equation: (NH4)(H2NCO2)(s) 2 NH3(g) + CO2(g) At 25 C, experiment shows that the total pressure of the gases in equilibrium with the solid is 0.116 atm. What is the equilibrium constant, Kp?In the gas phase, acetic acid exists as an equilibrium of monomer and dimer molecules. (The dimer consists of two molecules linked through hydrogen bonds.) The equilibrium constant, Kc, at 25 C for the monomer-dimer equilibrium 2 CH3CO2H (CH3CO2H)2 has been determined to be 3.2 104. Assume that acetic acid is present initially at a concentration of 5.4 104 mol/L at 25 C and that no dimer is present initially. (a) What percentage of the acetic acid is converted to dimer? (b) As the temperature increases, in which direction does the equilibrium shift? (Recall that hydrogen-bond formation is an exothermic process.)Assume 3.60 mol of ammonia is placed in a 2.00-L vessel and allowed to decompose to the elements at 723 K. 2 NH3(g) N2(g) + 3 H2(g) If the experimental value of Kc is 6.3 for this reaction at the temperature in the reactor, calculate the equilibrium concentration of each reagent. What is the total pressure in the flask?The total pressure for a mixture of N2O4 and NO2 is 0.15 atm. If Kp = 7.1 (at 25 C), calculate the partial pressure of each gas in the mixture. 2 NO2(g) N2O4(g)Kc for the decomposition of ammonium hydrogen sulfide is 1.8 104 at 25 C. NH4HS(s) NH3(g) + H2S(g) (a) When the pure salt decomposes in a flask, what are the equilibrium concentrations of NH3 and H2S? (b) If NH4HS is placed in a flask already containing 0.020 mol/L of NH3 and then the system is allowed to come to equilibrium, what are the equilibrium concentrations of NH3 and H2S?52GQ A 15-L flask at 300 K contains 6.44 g of a mixture of NO2 and N2O4 in equilibrium. What is the total pressure in the flask? (Kp for 2 NO2 (g) N2O4(g) is 7.1.)Lanthanum oxalate decomposes when heated to lanthanum(III) oxide, CO, and CO2. La2(C2O4)3(s) La2CO3(s) + 3 CO(g) + 3 CO2(g) (a) If, at equilibrium, the total pressure in a 10.0-L flask is 0.200 atm, what is the value of Kp? (b) Suppose 0.100 mol of La2(C2O4)3 was originally placed in the 10.0-L flask. What quantity of La2(C2O4)3 remains unreacted at equilibrium at 373 K?The reaction of hydrogen and iodine to give hydrogen iodide has an equilibrium constant, Kc, of 56 at 435 C. (a) What is the value of Kp? (b) Suppose you mix 0.045 mol of H2 and 0.045 mol of I2 in a 10.0-L flask at 425 C. What is the total pressure of the mixture before and after equilibrium is achieved? (c) What is the partial pressure of each gas at equilibrium?Sulfuryl chloride, SO2Cl2 is used as a reagent in the synthesis of organic compounds. When heated to a sufficiently high temperature, it decomposes to SO2 and Cl2. SO2Cl2(g) SO2(g) + Cl2(g)Kc = 0.045 at 375 C (a) A 10.0-L flask containing 6.70 g of SO2Cl2 is heated to 375 C. What is the concentration of each of the compounds in the system when equilibrium is achieved? What fraction of SO2Cl2 has dissociated? (b) What are the concentrations of SO2Cl2, SO2, and Cl2 at equilibrium in the 10.0-L flask at 375 C if you begin with a mixture of SO2Cl2 (6.70 g) and Cl2 (0.10 atm)? What fraction of SO2Cl2 has dissociated? (c) Compare the fractions of SO2Cl2 in parts (a) and (b). Do they agree with your expectations based on Le Chateliers principle?Hemoglobin (Hb) can form a complex with both O2 and CO. For the reaction HbO2(aq) + CO(g) HbCO(aq) + O2(g) at body temperature, K is about 200. If the ratio [HbCO]/[HbO2) comes close to 1, death is probable. What partial pressure of CO in the air is likely to be fatal? Assume the partial pressure of O2 is 0.20 atm.Limestone decomposes at high temperatures. CaCO3(s) CaO(s) + CO2(g) At 1000 C, Kp = 3.87. If pure CaCO3 is placed in a 5.00-L flask and heated to 1000 C, what quantity of CaCO3 must decompose to achieve the equilibrium pressure of CO2?At 1800 K, oxygen dissociates very slightly into its atoms. O2(g) 2 O(g)KP= 1.2 1010 If you place 0.050 mol of O2 in a 10.-L vessel and heat it to 1800 K, how many O atoms are present in the flask?Nitrosyl bromide, NOBr, dissociates readily at room temperature. NOBr(g) NO(g) + Br2(g) Some NOBr is placed in a flask at 25 C and allowed to dissociate. The total pressure at equilibrium is 190 mm Hg and the compound is found to be 34% dissociated. What is the value of Kp?A Boric acid and glycerin form a complex B(OH)3(aq) + glycerin(aq) B(OH)3 glycerin(aq) with an equilibrium constant of 0.90. If the concentration of boric acid is 0.10 M, how much glycerin should be added, per liter, so that 60.% of the boric acid is in the form of the complex?The dissociation of calcium carbonate has an equilibrium constant of Kp = 1.16 at 800 C. CaCO3(s) CaO(s) + CO2(g) (a) What is Kc for the reaction? (b) If you place 22.5 g of CaCO3 in a 9.56-L container at 800 C, what is the pressure of CO2 in the container? (c) What percentage of the original 22.5-g sample of CaCO3 remains undecomposed at equilibrium?A sample of N2O4 gas with a pressure of 1.00 atm is placed in a flask. When equilibrium is achieved, 20.0% of the N2O4 has been convened to NO2 gas. (a) Calculate Kp. If the original pressure of N2O4 is 0.10 atm, what is the percent dissociation of the gas? Is the result in agreement with Le Chateliers principle?64GQ The photograph below shows what occurs when a solution of potassium chromate is treated with a few drops of concentrated hydrochloric acid. Some of the bright yellow chromate ion is converted to the orange dichromate ion. 2 CrO42(aq) + 2 H3O+(aq) CrO72(aq) + 3 H2O() (a) Explain this experimental observation in terms of Le Chateliers principle. (b) What would you observe if you treated the orange solution with sodium hydroxide? Explain your observation.The photographs below (a) show what occurs when a solution of iron(III) nitrate is treated with a few drops of aqueous potassium thiocyanate. The nearly colorless iron(III) ion is converted to a red [Fe(H2O)5SCN)2+ ion. (This is a classic test for the presence of iron(III) ions in solution.) [Fe(H2O)6]3+(aq) + SCN(aq) [Fe(H2O)5SCN]2+(aq) + H2O() (a) As more KSCN is added to the solution, the color becomes even more red. Explain this observation. (b) Silver ions form a white precipitate with SCN ions. What would you observe on adding a few drops of aqueous silver nitrate to a red solution of [Fe(H2O)5 SCN]+ ions? Explain your observation.Decide whether each of the following statements is true or false. If false, change the wording to make it true. (a) The magnitude of the equilibrium constant is always independent of temperature. (b) When two chemical equations are added to give a net equation, the equilibrium constant for the net equation is the product of the equilibrium constants of the summed equations. (c) The equilibrium constant for a reaction has the same value as K for the reverse reaction. (d) Only the concentration of CO2 appears in the equilibrium constant expression for the reaction CaCO3(s) CaO(s) + CO2(g). (e) For the reaction CaCO3(s) CaO(s) + CO2(g), the value of K is numerically the same, whether the amount of CO2 is expressed as moles/liter or as gas pressure.Neither PbCl2 nor PbF2 is appreciably soluble in water. If solid PbCl2 and solid PbF2 are placed in equal amounts of water in separate beakers, in which beaker is the concentration of Pb2+ greater? Equilibrium constants for these solids dissolving in water are as follows: PbCl2(s) Pb2+(aq) + 2 Cl(aq)Kc = 1.7 105 PbF2(s) Pb2+(aq) + 2 F(aq)Kc = 3.7 108 Characterize each of the following as product- or reactant-favored at equilibrium. (a) CO(g) + O2(g) CO2(g)Kp = 1.2 1045 (b) H2O(g) H2(g) + O2(g)Kp = 9.1 1041 (c) CO(g) + Cl2(g) COCl2(g)Kp = 9.1 1011 The size of a flask containing colorless N2O4(g) and brown NO2(g) at equilibrium is rapidly reduced to half the original volume. N2O4(g) 2 NO2(g) (a) What color change (if any) is observed immediately upon halving the flask size? (b) What color change (if any) is observed during the process in which equilibrium is reestablished in the flask?Describe an experiment that would allow you to prove that the system 3 H2(g) + N2(g) 2 NH3(g) is a dynamic equilibrium. (Hint: Consider using a stable isotope such as 15N or 2H.)The chapter opening photograph (page 670) showed how the cobalt(II) chloride equilibrium responded to temperature changes. (a) Look back at that photograph. Is the conversion of the red cation to the blue anion exothermic or endothermic? (b) If hydrochloric acid is added to the violet mixture of cobalt(II) ions shown below, the blue CoCl42 ion is favored. If water is then added to the mixture, a red solution favoring [Co(H2O)]2+ results. Explain these observations in terms of Le Chateliers principle. (c) How do these observations prove the reaction is reversible?Suppose a tank initially contains H2S at a pressure of 10.00 atm and a temperature of 800 K. When the reaction has come to equilibrium, the partial pressure of S2 vapor is 0.020 atm. Calculate Kp. 2 H2S(g) 2 H2(g) + S2(g)Pure PCl5 gas is placed in a 2.00-L flask. After heating to 250 C the pressure of PCl5 is initially 2.000 atm. However, the gas slowly but only partially decomposes to gaseous PCl3 and Cl2. When equilibrium is reached, the partial pressure of Cl2 0.814 atm. Calculate Kp for the decomposition.What are the hydronium ion and hydroxide ion concentrations in 4.0 103 M HCI(aq) at 25 C? (Recall that because HCl is a strong acid, it is 100% ionized in water.)For each of the following salts in water, predict whether the pH will be greater than, less than, or equal to 7. (a) KBr (b) NH3NO3 (c) AlCl3 (d) Na2HPO4 (a) Which is the stronger Bronsted acid, HCO3 or NH4+? Which has the stronger conjugate base? (b) Is a reaction between HCO3- ions and NH3 product- or reactant-favored at equilibrium? HCO3(aq) + NH3(aq) CO32(aq) + NH4+(aq) (c) You mix solutions of sodium hydrogen phosphate and ammonia. The net ionic equation for a possible reaction is HPO42(aq) + NH3(aq) PO43(aq) + NH4+(aq) Does the equilibrium lie to the left or to the right for this reaction?A solution prepared from 0.055 mol of butanoic acid and sufficient water to give 1.0 L of solution has a pH of 2.72. Determine Ka for butanoic acid. The acid ionizes according to the balanced equation CH3CH2CH2CO2H(aq) + H2O(l) H3O+(aq) + CH3CH2CH2CO2(aq)What are the equilibrium concentrations of acetic acid, the acetate ion, and H3O+ for a 0.10 M solution of acetic acid (K2 = 1.8 105)? What is the pH of the solution?What are the equilibrium concentrations of HF, F ion, and H3O+ ion in a 0.00150 M solution of HF? What is the pH of the solution?The weak base, CIO (hypochlorite ion), is used in the form of NaCIO as a disinfectant in swimming pools and water treatment plants. What are the concentrations of HCIO and OH and the pH of a 0.015 M solution of NaCIO?Calculate the pH after mixing 15 mL of 0.12 M acetic acid with 15 ml of 0.12 M NaOH. What are the major species in solution at equilibrium (besides water), and what are their concentrations?What is the pH of a 0.10 M solution of oxalic acid, H2C2C4? What are the concentrations of H3O+, HC2O4, and the oxalate ion, C2O42? (See Appendix H for Ka values.)1.1ACP 1.2ACP The pKa, of the conjugate acid of atropine is 4.35. How does this compare with the pKa values for the conjugate acids of ammonia, methylamine, and aniline?Convert the pK values to K values for the ionization of HCl, HClO4, and H2SO4 in glacial acetic acid. Rank these acids in order from strongest to weakest.Other solvents also undergo autoionization. (a) Write a chemical equation for the autoionization of glacial acetic acid. (b) The equilibrium constant for the autoionization of glacial acetic acid is 32 1015 at 25C. Determine the concentration of [CH3CO2H2]+ in acetic acid at 25C.2.3ACP 2.4ACP To measure the relative strengths of bases stronger than OH, it is necessary to choose a solvent that is a weaker acid than water. One such solvent is liquid ammonia. (a) Write a chemical equation for the autoionization of ammonia. (b) What is the strongest acid and base that can exist in liquid ammonia? (c) Will a solution of HCI in liquid ammonia be a strong electrical conductor, a weak conductor, or a nonconductor? (d) Oxide ion (O2) is a stronger base than the amide ion (NH2). Write an equation for the reaction of O2 with NH3 in liquid ammonia. Will the equilibrium favor products or reactants?Write the formula and the give the name of the conjugate base of each of the following acids. a) HCN b) HSO4 c) HF Write the formula and give the name of the conjugate base of each of the following acids. a) NH3 b) HCO3 c) Br What are the products of each of the following acid-base reactions? Indicate the acid and its conjugate base and the base and its conjugate acid. a) HNO3+H2O b) HSO4+H2O c) sH3O++F What are the products of each of the following acid-base reactions? Indicate the acid and its conjugate base and the base and its conjugate acid. (a) HCIO4 + H2O (b) NH4 ++ H2O (c) HCO3 + OH Write balanced equations showing how the hydrogen oxalate ion, HC2O4, can be both a Bronsted acid and a Bronsted base.Write a balanced equation showing how the HPO42 ion of sodium hydrogen phosphate Na2HPO4 can be a both conjugated acid and conjugated base.In each of the following acid-base reactions, identify the Brnsted acid and base on the left and their conjugate partners on the right. (a) HCO2H(aq) + H2O() HCO2(aq) + H3O+(aq) (b) NH3(aq) + H2S(aq) NH4+(aq) + HS(aq) (c) HSO4(aq) + OH(aq) SO42(aq) + H2O+()In each of the following acid-base reactions, identify the Brnsted acid and base on the left and their conjugate partners on the right. (a) C2H5N(aq) + CH3CO2H(aq) C5H5NH+(aq) + CH3CO2(aq) (b) N2H4(aq) + HSO4(aq) N2H5+(aq) + SO42(aq) (c) [Al(H2O)6]3+ (aq) + OH(aq) [Al(H2O)5OH]2+ (aq) + H2O+()An aqueous solution has a pH of 3.75. What is the hydronium ion concentration of the solution? Is it acidic or basic?A saturated solution of milk of magnesia. Mg(OH)2, has a pH of 10.52. What is the hydronium ion concentration of the solution? What is the hydroxide ion concentration? Is the solution acidic or basic?What is the pH of a 0.0075 M solution of HCl? What is the hydroxide ion concentration of the solution?What is the pH of a 1.2 104 M solution of KOH? What is the hydronium ion concentration of the solution?What is the pH of a 0.0015 M solution of Ba(OH)2?The pH of a solution of Ba(OH)2 is 10.66 at 25 . What is the hydroxide ion concentration in the solution? If the solution volume is 125 mL, what mass of Ba(OH)2 must have been dissolved?Write an equilibrium constant expression for the reaction of ammonium ion, a weak acid, with water.Write an equilibrium constant expression for the reaction of fluoride ion, a weak base, with water.Several acids are listed here with their respective equilibrium constants: C6H5OH(aq) + H2O() H3O+(aq) + C6H5O(aq) Ka = 1.3 1010 HCO2H(aq) + H2O() H3O+(aq) + HCO2(aq) Ka = 1.8 104 HC2O4(aq) H2O() H3O+(aq) + C2O42(aq) Ka = 6.4 105 (a) Which is the strongest acid? Which is the weakest acid? (b) Which acid has the weakest conjugate base? (c) Which acid has the strongest conjugate base?Several acids are listed here with their respective equilibrium constants: HF(aq) + H2O() H3O+(aq) + F(aq) Ka = 7.2 104 HPO42(aq) + H2O() H3O+(aq) + PO43(aq) Ka = 3.6 1013 CH3CO2(H) + H2O() H3O+(aq) + CH3CO2(aq) Ka = 1.8 105 (a) Which is the strongest acid? Which is the weakest acid? (b) What is the conjugate base of the acid I IF? (c) Which acid has the weakest conjugate base? (d) Which acid has the strongest conjugate base?

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