Borax Analysis

b) Determine the standard enthalpy change and std. Gibbs free energy change of D reaction at 400 k for the reaction CO(g) +2H2(g) → CH;OH (g) At 298.15 K, AH CO (9)= -26.41 kcal/mol, AH.CH,0H(9)= -48.08 kcal/mol, (9)= -32.8079 kcal/mol, AG CH30H(g)= -38.69 kcal/mol, The standard heat capacity of various components is given by, C = a + bT + cT2 + dT³, where C is in cal/mol-K and T is in K b x10² c x105 d x10º Сomponent CH3OH a 4.55 2.186 -0.291 -1.92 CO 6.726 0.04 0.1283 -0.5307 H2 6.952 -0.0457 0.09563 -0.2079

The data below show the temperature variation of the equilibrium constant of the reaction: Ag2CO3 (s) → Ag2O (s) + CO2 (g) Calculate the standard reaction enthalpy ΔrH of this reaction.

There are many organic acids and bases in our cells, and their presence modifies the pH of the fluids inside them. It is useful to be able to assess the pH of solutions of acids and bases and to make inferences from measured values of the pH. A solution of equal concentrations of lactic acid and sodium lactate was found to have pH= 3.08. (a) What are the values of pKa and Ka of lactic acid? (b) What would the pH be if the acid had twice the concentration of the salt?

Calculate the solubility of Ca(OH)2(s) (Ksp = 1.6 x 10–15) in an aqueous solution buffered to pH 8.0. Show your work and justify any approximations made.

21.

A highly acidic (pH< 0.5) industrial wastewater has an initial AlP" concentration of 10 ppm. An engineer decides that strong base should be added to the wastewater in order to raise the pH so that most of the aluminum will precipitate and be removed from solution. The pertinent solubility reaction from Appendix A of our text is: Al(OH)3 (s) → Al* + 30H¯ with pK, = 32.9 a. What is the lowest pH needed to precipitate all but 50 ppb of the aluminum from the wastewater? Assume equilibrium conditions can be achieved. b. Suppose the engineer decides that the pH should be raised to 7. What equilibrium concentration of aluminum would be left in solution? Report your answer in ppb and moles per liter.

The standard enthalpy of combustion of the solid glycine (NH₂CH₂COOH) is -969 kJ/mol at 298 K. It's standard molar entropy is 103.5 J/K-mol. Calculate the standard Gibbs energy of formation of glycine at 298 K. Note that the nitrogen-containing species produced in the combustion reaction is N₂(g).

Sulfuric acid (H2SO4) is a diprotic acid where the first deprotonation is a strong acid process, and the second deprotonation is a weak acid process with Ka = 1.0 x 10-2. What is the pH of a 0.00075 M solution of sulfuric acid?

Write a molecular equation for the reaction between aqueous HBrHBr and aqueous Ba(OH)2Ba(OH)2. Express your answer as a chemical equation including phases.

See image below. Can you please show me how to solve this problem?

11.(a) 10.06 cm3 of the stock 0.100 mol dm–3 solution of NaOH was required to fully neutralise 49.5 mg of a diprotic acid (H2A). Write a balanced equation for this reaction and hence determine the molar mass (Mr) of the acid.                                                                                                                 (b) Determine the pH of 0.100 mol dm–3 NaOH at 298 K [pKw = 14.0].

Explain how you would analyse Fe(OX).2H2O for iron and oxalate if you were provided with a standardised solution of potassium permanganate, dilute sulphuric acid and zinc dust.

What is the value of pk, for the fluoride anion, F at 25°C? Ka(HF) = 7.1 x 10-4? Express your answer in decimal notation rounded to three significant figures.

The Ksp value for magnesium arsenate [Mg3(AsO4)2] is 2.00 X 10-20 so if a chemist added 1.19 x 10-2 M of Pb3(AsO4)2(aq)  which is a common ion then what would be the concentration of the Magnesium ion Mg2+(aq) in Molarity at equilibrium?   3.89 x 10-6   4.07 x 10-6   3.47 x 10-6   2.45 x 10-6   2.81 x 10-6   3.28 x 10-6   2.64 x 10-6   3.69 x 10-6   3.01 x 10-6   4.29 x 10-6

Magnesium metal (a component of alloys used in aircraft and a reducing agent used in the production of uranium, titanium, and other active metals) is isolated from sea water by the following sequence of reactions:Mg2+(aq) + Ca(OH)2(aq) ⟶ Mg(OH)2(s) + Ca2+(aq)Mg(OH)2(s) + 2HCl(aq) ⟶ MgCl2(s) + 2H2 O(l)MgCl2(l) ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯→ electrolysis Mg(s) + Cl2(g)Sea water has a density of 1.026 g/cm3 and contains 1272 parts per million of magnesium as Mg2+(aq) by mass. What mass, in kilograms, of Ca(OH)2 is required to precipitate 99.9% of the magnesium in 1.00 × 103 L of sea water?

electrochemistry. Will it be possible to do a reliable separation of methanol (boiling point 64.7o C) and ethanol (boiling point 78.5o C) in a distillation process? Explain your answer.

What is the accepted value for the Ksp of Ca(OH)2, including the conditions for its determination?

The standard state free energy of hydrolysis of phosphocreatine is ΔG° = -42.8 kJ/mol. phosphocreatine + H2O → creatine + Pi T = 20 °C Calculate the free energy change for the phosphocreatine hydrolysis in a solution of 3.50 mM creatine, 3.50 mM phosphate and 1.00 nM phosphocreatine.

A Mg Mg2+ || Co²+ | Co galvanic cell is constructed in which the standard cell voltage is 2.09 V. Calculate the free energy change at 25°C when 0.906 of Co plates out, if all concentrations remain at their standard value of 1 M throughout the process. What is the maximum amount of work that could be done by the cell on its surroundings during this experiment? AG⁰ = Maximum work = J J

4. Determine the changes in the molar volume, A,V°, for each of the reactions: a. 2H+(aq) = H2(g) Why is your answer so large? b. NaCl(s,halite) = Na+ (aq) + Cl(aq) How can aqueous species have negative molar volumes?

please answer 3.B (iii)

Calculate the standard enthalpy of formation of NOCI of the reaction Nz+ 1/2 One) + 1/2 Cla NOCI ( from the enthalpy of formation of NO given in 1/2 Nae + 1/2 Oza→ NO) 2NOCI AH = 90.25 KJ/mol AH = 75.5 KJ/mol - 2NO) + Clue)

What is the equilibrium constant for the following reaction that occurs when disodium citrate(Na2HC6H5O7) dissolves in water at 25ºC? The acid dissociation constants for citric acid, H3C6H5O7 , are:Ka1 = 7.4 × 10–4 , Ka2 =1.7 × 10–5 , and Ka3 = 4.0 × 10–7 . HC6H5O72– (aq) + H2O(l) ⇌ H2C6H5O7– (aq) + OH– (aq)

5. The oxidation of ferrous iron (Fe2+) to ferric ion (Fe³+) by molecular oxygen can be described by the following reaction: 4Fe²+ (aq) + O₂(aq) + 4H*(aq) = 4Fe³+ (aq) + 2H₂O(l) (1) Using free energies of formation, calculate the equilibrium constant for this reaction at 25 deg C. (2) For a water in equilibrium with the atmosphere, a pH of 2.0, and a total soluble iron concentration of 1 mg/L, calculate the concentrations of Fe2+(aq) and Fe³+(aq).

The contractions of the heart are controlled by electrical phenomena, as are nerve impulses throughout the body. The pulses of electricity that cause the heart to beat result from a remarkable combination of electrochemistry and the properties of semipermeable membranes. Cell walls are membranes with variable permeability with respect to number of physiologically important ions. Especially Na+, K+ and Ca²+. The concentrations of these ions are different for the fluids inside the cells (intracellular fluid, ICF) and outside the cells (extracellular fluid, ECF). Changes in the relative concentration of the ions in the ECF and ICF lead to changes in the emf of the voltaic cell. For example, in cardiac muscle cells, the concentration of K* in the ICF and ECF are typically about 135mM, and 4mM, respectively. [K*]₁cf = 135mM, [K*]µ£cf = 4mM. Can you calculate a potential difference which results in the concentration of K+ ions between ICF and ECF using the Nernst equation at the…

An aqueous sodium chloride solution is electrolyzed using a current of 4.42 A. How much time (min) is required to collect 15.5 L of chlorine if the gas is collected over water at 20.0°C ánd the total pressure is 107.5 kPa? Assume that the water is already saturated with chlorine so no more dissolves. Assume Ptotal(gas) P(Cl2,g) + P(H20,g) and that the correction for column height is negligible. The vapor pressure of water at 20.0°C is 2.34 kPa, F = 96485 C/mol e". and R = 8.314 kPa-L-mol1.K´1 Enter your final answer for the time required in units of minutes. Include only the numerical answer (no units).

The amino acid serine has two pKa values, one for its carbonyl group (pKa = 2.21) and one for its NH3+ group (pKa = 9.15).These pKa values help to determine the isoelectric pH (also known as the isoelectric point, pI). The pI is the pH at which the substance has a charge of zero. It affects how the amino acid moves in gels of different pH values during electrophoresis.

An aqueous solution of an unknown salt of rhodium is electrolyzed by a current of 2.50 A passing for 51.0 min. If 2.720 g Rh is produced at the cathode, what is the charge on the rhodium ions in solution? (Enter your answer using the format +1 and -2.)

A highly acidic (pH<0.5) industrial wastewater has an initial AP* concentration of 10 ppm. An engineer decides that strong base should be added to the wastewater in order to raise the pH so that most of the aluminum will precipitate and be removed from solution. The pertinent solubility reaction from Appendix A of our text is: Al(OH); (s) → A* + 3OH¯ with pK, = 32.9 a. What is the lowest pH needed to precipitate all but 50 ppb of the aluminum from the wastewater? Assume equilibrium conditions can be achieved. b. Suppose the engineer decides that the pH should be raised to 7. What equilibrium concentration of aluminum would be left in solution? Report your answer in ppb and moles per liter.

Can precipitation give a confirmatory result on Group V cations: K, Na, and NH4?