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You may have noticed that when water boils, you can seebubbles that rise to the surface of the water. What is inside these bubbles? Explain. a. air b. hydrogen and oxygen gas c. oxygen gas d. water vapor e. carbon dioxide gas Which of the following is true about an individual atom? a. An individual atom should be considered a solid. b. An individual atom should be considered a liquid. c. An individual atom should be considered a gas. d. The state of the atom depends on which element it is. e. An individual atom cannot be considered a solid, liquid,or gas. Justify your choice, and for those you did not choose,explain why they are incorrect.How would you go about finding the number of “chalkmolecules” it takes to write your name on the board?Explain what you would need to do and provide a samplecalculation.These questions concern the work of J. J. Thomson: a. From what you know of Thomson’s work, whichparticles do you think he would believe are mostimportant in the formation of compounds (chemicalchanges) and why? b. Of the remaining two subatomic particles, which doyou place second in importance for forming compoundsand why? c. Propose three models that explain Thomson’s findingsand evaluate them. Include Thomson’s findings.Heat is applied to an ice cube in a closed container untilonly steam is present. Draw a representation of this process,assuming you can see it at an extremely high level ofmagnification. What happens to the size of the molecules?What happens to the total mass of the sample?You have a chemical in a sealed glass container filled withair. The setup is sitting on a balance, as shown. The chemicalis ignited by means of a magnifying glass focusing sunlighton the reactant. After the chemical has completely burned,which of the following is true? Explain your answer. a. The balance will read less than 250.0 g. b. The balance will read 250.0 g. c. The balance will read greater than 250.0 g. d. Cannot be determined without knowing the identityof the chemical.7DQ One of the best indications of a useful theory is that itraises more questions for further experimentation than itoriginally answered. Is this true of Dalton’s atomic theory?Give examples.9DQ How does Dalton’s atomic theory account for each of the following? The law of conservation of mass The law of definite proportion The law of multiple proportions What refinements had to be made in Dalton’s atomictheory to account for Gay-Lussac’s results on the combiningvolumes of gases?Which (if any) of the following can be determined by knowing the number of protons in a neutral element?Explain your answer. a. the number of neutrons in the neutral element b. the number of electrons in the neutral element c. the name of the element The average mass of a carbon atom is 12.011. Assumingyou were able to pick up only one carbon atom, thechance that you would randomly get one with a mass of12.011 is a. 0%. b. 0.011%. c. about 12%. d. 12.011%. e. greater than 50%. f. None of these is true. Explain.Which of the following explain how an ion is formed?Explain your answer. a. adding or subtracting protons to/from an atom b. adding or subtracting neutrons to/from an atom c. adding or subtracting electrons to/from an atom 15DQ 16DQ Why is calcium dichloride not the correct systematicname for CaCl2 ?Explain the law of conservation of mass, the law of definiteproportion, and the law of multiple proportions.19E When mixtures of gaseous H2 and gaseous Cl2 react, aproduct forms that has the same properties regardless ofthe relative amounts of H2 and Cl2 used. a. How is this result interpreted in terms of the law ofdefinite proportion? b. When a volume of H2 reacts with an equal volume of Cl2 at the same temperature and pressure, what volumeof product having the formula HCl is formed?Observations of the reaction between nitrogen gas andhydrogen gas show us that 1 volume of nitrogen reactswith 3 volumes of hydrogen to make 2 volumes of gaseousproduct, as shown below: Determine the formula of the product and justify youranswer.22E Hydrazine, ammonia, and hydrogen azide all contain onlynitrogen and hydrogen. The mass of hydrogen that combineswith 1.00 g of nitrogen for each compound is 1.4410-1g,2.1610-1g,and2.4010-2g ,respectively. Show how these data illustrate the law ofmultiple proportions.Consider 80.0-g samples of two different compounds consisting of only carbon and oxygen. One of the compounds consists of 21.8 g of carbon, and the other has34.3 g of carbon. Determine the ratio in whole numbersof the masses of carbon that combine with 1.00 g of oxygen between the two compounds.Early tables of atomic weights (masses) were generated bymeasuring the mass of a substance that reacts with 1.00 gof oxygen. Given the following data and taking theatomic mass of hydrogen as 1.00, generate a table of relativeatomic masses for oxygen, sodium, and magnesium. How do your values compare with those in the periodictable? How do you account for any differences?What evidence led to the conclusion that cathode rayshad a negative charge? Is there a difference between acathode ray and a particle?27E 28E A chemist in a galaxy far, far away performed the Millikanoil drop experiment and got the following resultsfor the charge on various drops. What is the charge of theelectron in zirkombs? 2.561012zirkmobs3.841012zirkmobs7.681012zirkmobs6.401013zirkmobs Do the proton and the neutron have exactly the samemass? How do the masses of the proton and the neutroncompare with the mass of the electron? Which particlesmake the greatest contribution to the mass of an atom?Which particles make the greatest contribution to thechemical properties of an atom?Consider Ernest Rutherford’s a-particle bombardmentexperiment illustrated in Fig. 2.11. How did the results ofthis experiment lead Rutherford away from the plumpudding model of the atom to propose the nuclear modelof the atom?Distinguish between the following terms. a. molecule versus ion b. covalent bonding versus ionic bonding c. molecule versus compound d. anion versus cation What is the distinction between atomic number and massnumber? Between mass number and atomic mass?34E a. List the noble gas elements. Which of the noble gaseshas only radioactive isotopes? (This situation is indicatedon most periodic tables by parentheses aroundthe mass of the element. See inside front cover.) b. Which lanthanide element and which transition elementhave only radioactive isotopes?Consider the elements of the carbon family: C, Si, Ge, Sn,and Pb. What is the trend in metallic character as one goesdown a group in the periodic table? What is the trend inmetallic character going from left to right across a periodin the periodic table?37E The number of protons in an atom determines the identityof the atom. What does the number and arrangement ofthe electrons in an atom determine? What does the numberof neutrons in an atom determine?For lighter, stable isotopes, the ratio of the mass numberto the atomic number is close to a certain value. What isthe value? What happens to the value of the mass numberto atomic number ratio as stable isotopes become heavier?For each of the following sets of elements, label each aseither noble gases, halogens, alkali metals, alkaline earthmetals, or transition metals. a. Ti, Fe, Ag b. Mg, Sr, Ba c. Li, K, Rb d. Ne, Kr, Xe e. F, Br, I 41E Write the atomic symbol (ZAX) for each of the isotopesdescribed below. a. number of protons =27, number of neutrons =31 b. the isotope of boron with mass number 10 c. Z=12,A=23 d. atomic number 53, number of neutrons =79 e. Z=9 , number of neutrons =10 f. number of protons =29, mass number 65 43E 44E 45E 46E Would you expect each of the following atoms to gain orlose electrons when forming ions? What ion is the mostlikely in each case? a. Ra c. P e. Br b. In d. Tef. Rb 48E The compounds AlCl3,CrCl3,andICl3 have similar formulas,yet each follows a different set of rules to name it.Name these compounds, and then compare and contrastthe nomenclature rules used in each case.Each of the following compounds has three possiblenames listed for it. For each compound, what is the correct name and why aren’t the other names used? a. N2O : nitrogen oxide, nitrogen(I) oxide, dinitrogenmonoxide b. Cu2O : copper oxide, copper(I) oxide, dicoppermonoxide c. Li2O : lithium oxide, lithium(I) oxide, dilithiummonoxide 51E 52E 53E 54E 55E 56E 57E 58E 59E 60E 61E 62AE 63AE What discoveries were made by J. J. Thomson, HenriBecquerel, and Lord Rutherford? How did Dalton’smodel of the atom have to be modified to account forthese discoveries?65AE 66AE A sample of chloroform is found to contain 12.0 g ofcarbon, 106.4 g of chlorine, and 1.01 g of hydrogen. If asecond sample of chloroform is found to contain 30.0 gof carbon, what is the total mass of chloroform in thesecond sample?In a reaction, 34.0 g of chromium(III) oxide reacts with12.1 g of aluminum to produce chromium and aluminumoxide. If 23.3 g of chromium is produced, what mass ofaluminum oxide is produced?69AE 70AE 71AE 72AE 73AE 74AE 75AE 76AE 77AE 78AE 79AE Identify each of the following elements. a. a member of the same family as oxygen whose moststable ion contains 54 electrons b. a member of the alkali metal family whose most stableion contains 36 electrons c. a noble gas with 18 protons in the nucleus d. a halogen with 85 protons and 85 electrons A certain element has only two naturally occurring isotopes:one with 18 neutrons and the other with 20 neutrons.The element forms 1-charged ions when in ioniccompounds. Predict the identity of the element. Whatnumber of electrons does the 1-charged ion have?82AE Which of the following is(are) correct? a. 40Ca2+ contains 20 protons and 18 electrons. b. Rutherford created the cathode-ray tube and was thefounder of the charge-to-mass ratio of an electron. c. An electron is heavier than a proton. d. The nucleus contains protons, neutrons, andelectrons.84AE 85AE Complete the following table to predict whether the givenatom will gain or lose electrons in forming the ion mostlikely to form when in ionic compounds.Which of the following statements is(are) correct? a. The symbols for the elements magnesium, aluminum,and xenon are Mn, Al, and Xe, respectively. b. The elements P, As, and Bi are in the same family onthe periodic table. c. All of the following elements are expected to gainelectrons to form ions in ionic compounds: Ga, Se,and Br. d. The elements Co, Ni, and Hg are all transitionelements. e. The correct name for TiO2 is titanium dioxide.88CP Each of the statements below is true, but Dalton mighthave had trouble explaining some of them with his atomictheory. Give explanations for the following statements. a. The space-filling models for ethyl alcohol anddimethyl ether are shown below. These two compounds have the same composition bymass (52% carbon, 13% hydrogen, and 35% oxygen),yet the two have different melting points, boilingpoints, and solubilities in water. b. Burning wood leaves an ash that is only a small fractionof the mass of the original wood. c. Atoms can be broken down into smaller particles. d. One sample of lithium hydride is 87.4% lithium bymass, whereas another sample of lithium hydride is74.9% lithium by mass. However, the two sampleshave the same properties.You take three compounds, each consisting of two elements(X, Y, and/or Z) and decompose them to their respectiveelements. To determine the relative masses of X,Y, and Z, you collect and weigh the elements, obtainingthe following data: a. What are the assumptions needed to solve thisproblem? b. What are the relative masses of X, Y, and Z? c. What are the chemical formulas of the threecompounds? d. If you decompose 21 g of compound XY, how muchof each element is present?Two elements, R and Q, combine to form two binarycompounds. In the first compound, 14.0 g of R combineswith 3.00 g of Q. In the second compound, 7.00 g of Rcombines with 4.50 g of Q. Show that these data are inaccord with the law of multiple proportions. If the formulaof the second compound is RQ, what is the formulaof the first compound?A single molecule has a mass of 7.3110223g . Providean example of a real molecule that can have this mass.A combustion reaction involves the reaction of a substancewith oxygen gas. The complete combustion of anyhydrocarbon (binary compound of carbon and hydrogen)produces carbon dioxide and water as the only products.Octane is a hydrocarbon found in gasoline. Completecombustion of octane produces 8 L of carbon dioxide forevery 9 L of water vapor (both measured at the sametemperature and pressure). What is the ratio of carbonatoms to hydrogen atoms in a molecule of octane?You have two distinct gaseous compounds made from elementX and element Y. The mass percents are as follows: Compound I: 30.43% X, 69.57% Y Compound II: 63.64% X, 36.36% Y In their natural standard states, element X and element Yexist as gases. (Monatomic? Diatomic? Triatomic? That isfor you to determine.) When you react “gas X” with “gasY” to make the products, you get the following data (allat standard pressure and temperature): 1volumegasX+2VolumesgasY2volumescompoundI2volumegasX+1VolumesgasY2volumescompoundII Assume the simplest possible formulas for reactants andproducts in these chemical equations. Then determine therelative atomic masses of element X and element Y.You have gone back in time and are working with Daltonon a table of relative masses. Following are his data: 0.602 g gas A reacts with 0.295 g gas B 0.172 g gas B reacts with 0.401 g gas C 0.320 g gas A reacts with 0.374 g gas C a. Assuming simplest formulas (AB, BC, and AC), construct a table of relative masses for Dalton. b. Knowing some history of chemistry, you tell Daltonthat if he determines the volumes of the gases reactedat constant temperature and pressure, he need notassume simplest formulas. You collect the following data: 6volumesgasA+1volumegasB4volumesproduct1volumegasB+4volumesgasC4volumesproduct3volumesgasA+2volumesgasC6volumesproduct Write the simplest balanced equations, and find theactual relative masses of the elements. Explain yourreasoning.1DQ Consider the equation A+2BAB2 . Imagine that10 moles of A is reacted with 26 moles of B. Use a scalefrom 0 to 10 to express your level of agreement witheach of the following statements. Justify and discussyour responses. a. There will be some As left over. b. There will be some Bs left over. c. Because of leftover As, some A2 molecules will beformed. d. Because of leftover Bs, some B2 molecules will beformed. e. Even if A is not limiting, A2 molecules will beformed. f. Even if B is not limiting, B2 molecules will beformed. g. Along with the molecule AB2 , molecules with theformula AxBy (other than AB2 ) will be formed.3DQ 4DQ 5DQ For the preceding question, which of the following equationsbest represents the reaction? a. 6N2+6H24NH3+4N2 b. N2+H2NH3 c. N+3HNH3 d. N2+3H22NH3 e. 2N2+6H24NH3 Justify your choice. For those you did not choose, explainwhy they are incorrect.7DQ A kerosene lamp has a mass of 1.5 kg. You put 0.5 kg ofkerosene in the lamp. You burn all the kerosene until thelamp has a mass of 1.5 kg. What is the mass of the gasesthat are given off? Explain.9DQ You may have noticed that water sometimes drips froman exhaust pipe of a car as it is running. Is this evidencethat there is at least a small amount of water originallypresent in the gasoline? Explain.11DQ 12DQ 13DQ Atoms of three different elements are represented by , , and . Which compound is left over when three moleculesof and three molecules of react to form and ?15DQ 16DQ 17DQ 18DQ Chlorine exists mainly as two isotopes, 37Cland35Cl .Which is more abundant? How do you know?According to the law of conservation of mass, mass cannotbe gained or destroyed in a chemical reaction. Whycan’t you simply add the masses of two reactants to determinethe total mass of product?21DQ 22DQ 23E 24E 25E 26E 27E An element consists of 1.40% of an isotope with mass203.973 u, 24.10% of an isotope with mass 205.9745 u,22.10% of an isotope with mass 206.9759 u, and52.40% of an isotope with mass 207.9766 u. Calculatethe average atomic mass and identify the element.29E Naturally occurring tellurium (Te) has the followingisotopic abundances: Draw the mass spectrum of H2Te , assuming that theonly hydrogen isotope present is 1H (mass 1.008).Gallium arsenide (GaAs) has gained widespread use insemiconductor devices that interconvert light and electricalsignals in fiber-optic communications systems.Galliumconsists of 60.% 69Ga and 40.% 71Ga . Arsenichas only one naturally occurring isotope, 75As . Galliumarsenide is a polymeric material, but its mass spectrumshows fragments with formulas GaAs and Ga2As2 . Whatwould the distribution of peaks look like for these twofragments?32E 33E 34E 35E How many atoms of nitrogen are present in 5.00 g ofeach of the following? a. glycine, C2H5O2N c. calcium nitrate b. magnesium nitride d. dinitrogen tetroxide Consider the following gas samples: 4.0 g of hydrogengas, 4.0 g of helium gas, 1.0 mole of fluorine gas, 44.0 gof carbon dioxide gas, and 146 g of sulfur hexafluoridegas. Arrange the gas samples in order of increasingnumberof total atoms present.38E 39E 40E 41E 42E In 1987 the first substance to act as a superconductor ata temperature above that of liquid nitrogen (77 K) wasdiscovered. The approximate formula of this substanceis YBa2Cu3O7 . Calculate the percent composition bymass of this material.44E 45E Vitamin B12 , cyanocobalamin, is essential for human nutrition.It is concentrated in animal tissue but not inhigher plants. Although nutritional requirements for thevitamin are quite low, people who abstain completelyfrom animalproducts may develop a deficiency anemia.Cyanocobalamin is the form used in vitamin supplements.It contains 4.34% cobalt by mass. Calculate the molarmass of cyanocobalamin, assuming that there is one atomof cobalt in every molecule of cyanocobalamin.47E 48E 49E Give the empirical formula of each of these compounds.Determine the molecular formulas to which the followingempirical formulas and molar masses pertain. a. SNH (188.35 g/mol) b. NPCl2 (347.64 g/mol) c. CoC4O4 (341.94 g/mol) d. SN (184.32 g/mol)A sample of urea contains 1.121 g N, 0.161 g H,0.480 g C, and 0.640 g O. What is the empirical formulaof urea?53E The compound adrenaline contains 56.79% C, 6.56%H, 28.37% O, and 8.28% N by mass. What is theempiricalformula of adrenaline?The most common form of nylon (nylon-6) is 63.68%carbon, 12.38% nitrogen, 9.80% hydrogen, and 14.14%oxygen. Calculate the empirical formula for nylon-6.56E 57E 58E 59E 60E 61E 62E 63E 64E 65E Iron oxide ores, commonly a mixture of FeOand Fe2O3 ,are given the general formula Fe3O4 . They yield elementaliron when heated to a very high temperature witheither carbon monoxide or elemental hydrogen. Balancethe following equations for these processes: Fe3O4(s)+H2(g)Fe(s)+H2O(g)Fe3O4(s)+CO2(g)Fe(s)+CO2(g)67E 68E 69E 70E 71E 72E Elixirs such as Alka-Seltzer use the reaction of sodiumbicarbonate with citric acid in aqueous solution to producea fizz: 3NaHCO3( aq)+C6H8O7( aq) 3CO2(g) +3H2O(l )+Na3C6H5O7(aq) a. What mass of C6H8O7 should be used for every 1.0102mgNaHCO3 ? b. What mass of CO2(g) could be produced from sucha mixture?74E 75E 76E 77E Bacterial digestion is an economical method of sewagetreatment. The reaction 5CO2(g)+55NH4+(aq)+76O2(g)BacteriaC5H7O2N(s)+54NO2(aq)+52H2O(l)+109H+(aq)Bacterialtissue is an intermediate step in the conversion of the nitrogenin organic compounds into nitrate ions. How muchbacterial tissue is produced in a treatment plant for every 1.0104kg of wastewater containing 3.0% NH4+ ions by mass? Assume that 95% of the ammonium ionsare consumed by the bacteria.79E 80E 81E 82E Hydrogen peroxide is used as a cleaning agent in thetreatment of cuts and abrasions for several reasons. It isan oxidizing agent that can directly kill many microorganisms;it decomposes upon contact with blood, releasingelemental oxygen gas (which inhibits the growthof anaerobic microorganisms); and it foams upon contactwith blood, which provides a cleansing action. In the laboratory, small quantities of hydrogen peroxidecan be prepared by the action of an acid on an alkalineearth metal peroxide, such as barium peroxide: BaO2(s)+2HCl(aq)H2O2(aq)+BaCl2(aq) What amount of hydrogen peroxide should result when1.50 g of barium peroxide is treated with 88.0 mL ofhydrochloric acid solution containing 0.0272 g of HClper mL? What mass of which reagent is left unreacted?Silver sulfadiazine burn-treating cream creates a barrieragainst bacterial invasion and releases antimicrobialagents directly into the wound. If 25.0 g of Ag2O is reactedwith 50.0 g of C10H10N4SO2 , what mass of silversulfadiazine (AgC10H9N4SO2) can be produced, assuming100% yield? Ag2O(s)+2C10H10N4SO2(s)2AgC10H9N4SO2(s)+H2O(l)Bornite (Cu3FeS3) is a copper ore used in the productionof copper. When heated, the following reaction occurs: 2Cu3FeS3(s)+7O2(g)6Cu(s)+2FeO(s)+6SO2(g) If 2.50 metric tons of bornite is reacted with excess O2 and the process has an 86.3% yield of copper, how muchcopper is produced?DDT, an insecticide harmful to fish, birds, and humans,is produced by the following reaction: 2C6H5Cl+C2HOCl3C14H9Cl5+H2OChlorobenzeneChloralDDT In a government lab, 1142 g of chlorobenzene is reactedwith 485 g of chloral. a. What mass of DDT is formed, assuming 100%yield? b. Which reactant is limiting? Which is in excess? c. What mass of the excess reactant is left over? d. If the actual yield of DDT is 200.0 g, what is thepercent yield?87E 88E 89E 90E 91AE 92AE A sample of a hydrocarbon (a compound consisting ofonly carbon and hydrogen) contains 2.591023 atomsof hydrogen and is 17.3% hydrogen by mass. If the molarmass of the hydrocarbon is between 55 and 65 g/mol,how many moles of compound are present, and what isthe mass of the sample?94AE 95AE The empirical formula of styrene is CH; the molar massof styrene is 104.14 g/mol. How many H atoms are presentin a 2.00-g sample of styrene?A 0.755-g sample of hydrated copper(II) sulfate (CuSO4xH2O) was heated carefully until it had changed completelyto anhydrous copper(II) sulfate (CuSO4) with amass of 0.483 g. Determine the value of x. [This numberis called the “number of waters of hydration” of copper(II)sulfate. It specifies the number of water molecules performula unit of CuSO4 in the hydrated crystal.]98AE 99AE 100AE 101AE 102AE 103AE 104AE 105AE 106AE 107AE 108AE 109AE 110AE 111AE 112AE 113AE 114AE 115AE 116AE 117AE 118AE 119AE Which of the following statements about chemical equationsis(are) true? a. When balancing a chemical equation, you can neverchange the coefficient in front of any chemicalformula. b. The coefficients in a balanced chemical equation referto the number of grams of reactants and products. c. In a chemical equation, the reactants are on theright and the products are on the left. d. When balancing a chemical equation, you can neverchange the subscripts of any chemical formula. e. In chemical reactions, matter is neither created nordestroyed so a chemical equation must have thesame number of atoms on both sides of theequation.121AE 122AE 123CP When the supply of oxygen is limited, iron metal reactswith oxygen to produce a mixture of FeOand Fe2O3 . Ina certain experiment, 20.00 g of iron metal was reactedwith 11.20 g of oxygen gas. After the experiment, theiron was totally consumed and 3.24 g of oxygen gasremained. Calculate the amounts of FeO and Fe2O3 formed in this experiment.Element X forms both a dichloride (XCl2) and a tetrachloride (XCl4) . Treatment of 10.00 g of XCl2 with excesschlorine forms 12.55 g of XCl4 . Calculate theatomic weight (mass) of X and identify X.Zinc and magnesium metal each react with hydrochloricacid to make chloride salts of the respective metals andhydrogen gas. A 10.00-g mixture of zinc and magnesiumproduces 0.5171 g of hydrogen gas upon being mixedwith an excess of hydrochloric acid. Determine the percentmagnesium by mass in the original mixture.An unknown binary compound containing hydrogen (XHn) has a density as a gas that is 2.393 times that ofoxygen gas under the same conditions. When 2.23102 mole of this compound reacts with excess oxygengas, 0.803 g of water is produced. Identify the element Xin this compound.A 2.25-g sample of scandium metal is reacted with excesshydrochloric acid to produce 0.1502 g hydrogengas. What is the formula of the scandium chloride producedin the reaction?When M2S3(s) is heated in air, it is converted to MO2(s) .A 4.000-g sample of M2S3(s) shows a decrease in massof 0.277 g when it is heated in air. What is the averageatomic mass of M?Consider a gaseous binary compound with a molar massof 62.09 g/mol. When 1.39 g of this compound is completelyburned in excess oxygen, 1.21 g of water isformed. Determine the formula of the compound.131CP You take 1.00 g of an aspirin tablet (a compound consistingsolely of carbon, hydrogen, and oxygen), burn itin air, and collect 2.20 g CO2 and 0.400 g H2O . Youknow that the molar mass of aspirin is between 170 and190 g/mol. Reacting 1 mole of salicylic acid with 1 moleof acetic anhydride (C4H6O3) gives you 1 mole of aspirinand 1 mole of acetic acid (C2H4O2) . Use this informationto determine the molecular formula of salicylic acid.Lanthanum was reacted with hydrogen in a given experimentto produce the nonstoichiometric compound LaH2.90 . Assuming that the compound contains H,La2+,andLa3+ , calculate the fraction of La2+andLa3+ present.134CP Consider a mixture of potassium chloride and potassiumnitrate that is 43.2% potassium by mass. What is thepercent KCl by mass of the original mixture?136CP 137CP A gas contains a mixture of NH3(g)andN2H4(g) , both ofwhich react with O2(g) to form NO2(g)andH2O(g) . Thegaseous mixture (with an initial mass of 61.00 g) is reactedwith 10.00 moles O2 , and after the reaction iscomplete, 4.062 moles of O2 remains. Calculate the masspercent of N2H4(g) in the original gaseous mixture.139MP 140MP 1DQ 2DQ 3DQ 4DQ 5DQ The exposed electrodes of a light bulb are placed in asolution of H2SO4 in an electrical circuit such that thelight bulb is glowing. You add a dilute salt solution, andthe bulb dims. Which of the following could be the saltin the solution? a. Ba(NO3)2 c. K2SO4 b. NaNO3 d. Ca(NO3)2 Justify your choices. For those you did not choose, explainwhy they are incorrect.7DQ 8DQ Consider separate aqueous solutions of HCland H2SO4 ,each with the same molar concentration. An aqueoussolution of NaOH is added to each solution to neutralizethe acid. Which acid solution requires the largestvolume of NaOH solution to react completely with the acid present? Explain.10DQ 11DQ Characterize strong electrolytes versus weak electrolytesversus nonelectrolytes. Give examples of each. How doyou experimentally determine whether a soluble substanceis a strong electrolyte, weak electrolyte, ornonelectrolyte.The figures below are molecular-level representations offour aqueous solutions of the same solute. Arrange thesolutions from most to least concentrated.14E Differentiate between what happens when the followingare dissolved in water. a. polar solute versus nonpolar solute b. KF versus C6H12O6 c. RbCl versus AgCl d. HNO3 versus CO Commercial cold packs and hot packs are available fortreating athletic injuries. Both types contain a pouch ofwater and a dry chemical. When the pack is struck, thepouch of water breaks, dissolving the chemical, and thesolution becomes either hot or cold. Many hot packs usemagnesium sulfate, and many cold packs use ammoniumnitrate. Write reaction equations to show how these strong electrolytes break apart in water.17E 18E 19E 20E 21E 22E 23E 24E 25E 26E 27E 28E 29E A stock solution containing Mn2+ ions is prepared bydissolving 1.584 g of pure manganese metal in nitricacid and diluting to a final volume of 1.000 L. The followingsolutions are prepared by dilution. For solution A, 50.00 mL of stock solution is diluted to1000.0 mL. For solution B, 10.00 mL of A is diluted to 250.0 mL. For solution C, 10.00 mL of B is diluted to 500.0 mL. Calculate the molar concentrations of the stock solutionand solutions A, B, and C.31E 32E List the formulas of three soluble bromide salts and threeinsoluble bromide salts. Do the same exercise for sulfatesalts, hydroxide salts, and phosphate salts (list three solublesalts and three insoluble salts). List the formulas forsix insoluble Pb2+ salts and one soluble Pb2+ salt.34E 35E 36E 37E 38E Write the balanced molecular, complete, and net ionicequations for the reaction, if any, that occurs when aqueoussolutions of the following are mixed. a. ammonium sulfate and barium nitrate b. lead(II) nitrate and sodium chloride c. sodium phosphate and potassium nitrate d. sodium bromide and rubidium chloride e. copper(II) chloride and sodium hydroxide How would you separate the following ions in aqueoussolution by selective precipitation? a. Ag+,Ba2+,andCr3+ b. Ag+,Pb2+,andCu2+ c. Hg22+andNi2+41E 42E 43E What volume of 0.100 M Na3PO4 is required to precipitateall of the lead(II) ions from 150.0 mL of 0.250 MPb(NO3)2 ?45E 46E 47E The following drawings represent aqueous solutions.Solution A is 2.00 L of a 2.00 M aqueous solution ofcopper(II) nitrate. Solution B is 2.00 L of a 3.00 M aqueoussolution of potassium hydroxide. a. Draw a picture of the solution made by mixingsolutions A and B together after the precipitationreaction takes place. Make sure this picture showsthe correct relative volume compared with solutionsA and B and the correct relative number of ions,along with the correct relative amount of solidformed. b. Determine the concentrations (in M) of all ions leftin solution (from part a) and the mass of solidformed.49E 50E 51E 52E Saccharin (C7H5NO3S) is sometimes dispensed in tabletform. Ten tablets with a total mass of 0.5894 g weredissolved in water. This solution was then oxidized toconvert all the sulfur to sulfate ion, which was precipitatedby adding an excess of barium chloride solution.The mass of BaSO4 obtained was 0.5032 g. What is theaverage mass of saccharin per tablet? What is the averagemass percent of saccharin in the tablets?54E A 1.42-g sample of a pure compound with formula M2SO4 was dissolved in water and treated with an excessof aqueous calcium chloride, resulting in the precipitationof all the sulfate ions as calcium sulfate. Theprecipitate was collected, dried, and found to weigh1.36 g. Determine the atomic mass of M and identify M.56E 57E 58E 59E 60E 61E 62E 63E Sodium hydroxide solution is usually standardized bytitrating a pure sample of potassium hydrogen phthalate( KHC8H4O4 , often abbreviated KHP), an acid with oneacidic hydrogen and a molar mass of 204.22 g/mol. Ittakes 34.67 mL of a sodium hydroxide solution to titratea 0.1082-g sample of KHP. What is the molarity ofthe sodium hydroxide?65E

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