In the procedure, you are asked to dilute the borax sample to about 25 mL with d

Question

In the procedure, you are asked to dilute the borax sample to about 25 mL with deionized water before the titrimetric analysis. Is this volume critical to the analysis? Explain. The molar solubility of silver sulfate, Ag_2SO_4 is 1.4 times 10^-2 mol/L. a. What is the solubility product for silver sulfate? b. Determine the standard free energy for the dissolution of silver sulfate at 25 degree C. The standard free energy change for a strong acid-strong base neutralization reaction at 25 degree C is -79.9 kJ. H_3O+(aq) + OH"(aq) rightarrow 2H_2O(l) Delta G degree = -79.9 kJ a. Calculate the equilibrium constant for the reaction b. If the standard enthalpy change for the reaction at 25 degree C is -57.8 kJ, determine the standard entropy change for the reaction at 25 degree C. c. Is the above chemical reaction spontaneous? Explain your answer

Explanation / Answer

Q1.

The volume is used to dilute borax..

the dilution will help us to handle it better in the lab and in calculations

Q2.

Ksp = [Ag+]^2[SO4-2]

so.

[Ag+] = 2*(1.4*10^-2)

[SO4-2] = (1.4*10^-2)

Ksp =(2*(1.4*10^-2))^2( (1.4*10^-2)) = 1.097*10^-5

b)

G = -RT*ln(Ksp)

G = -8.314*298*ln(1.097*10^-5 = 28294.73 J/mol = 28.294 kJ/mol

Q3

a)

G = -RT*ln(K)

K = exp(-G/(RT))

K = exp(79900/(8.314*298)) =1.01321*10^-14

b)

if HRxn formation = -57.8 kJ

find entropy

dS = dH/T =  -57800 /(298) = -193.95 J/molL

c)

it must be spontanous, sicne dG is negative

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