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Thermodynamics

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Wize University Chemistry Textbook > Thermodynamics Part 2: (2nd Law-entropy, 3rd Law, Gibbs Free Energy, Spontaneity)

3rd Law of Thermodynamics

2 Activities

Wize University Chemistry Textbook > Thermodynamics Part 2: (2nd Law-entropy, 3rd Law, Gibbs Free Energy, Spontaneity)

Connecting Gibbs Free Energy and Equilibrium

7 Activities

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The Solubility Constant for AgI(s) at 25oC is 8.3x10-17. What is ΔG(rxn) given that the current concentrations of ions are: [Ag+]=9.1x10-9 & [I-]=9.1x10-9

1)Write the variables we know/trying to solve for


2) Out of the different equations for deltaG, which one should we use?

1)∆G=∆Go +RTlnQ
2)∆Go=-RTlnK
3)∆G=RTln(Q/K)


3) Solve for Q


4) Solve for ∆G:


Part 2: What if the question had asked you to solve for ∆Go? (ans. in kJ/mol)


More 3rd Law of Thermodynamics Questions:
The Haber Bosch Process is an industrial process for “fixing” nitrogen, shown below. This process produces around 500 million tons of ammonia every year.
ΔfG0(NH3)=−16.4 kJ/mol\Delta_fG^0(NH_3)=-16.4\ kJ/mol
3/2 H2(g)+1/2 N2(g)→NH3(g)\rm 3/2\ H_{2(g)}\quad+\quad 1/2\ N_{2(g)}\quad\overrightarrow{\hspace{1.5cm}}\quad NH_{3(g)}
Entropy
Calculate the standard molar entropy change for the combustion of methane (J/mol K).
CH4 (g) + 2 O2 (g) →\rightarrow CO2 (g) + 2 H2O (g)
Thermodynamics
Which of the following statements disagrees with the laws of thermodynamics?
Thermodynamics
Indicate the FALSE statement about the laws of thermodynamics:
More Connecting Gibbs Free Energy and Equilibrium Questions:
Use the following reactions to answer the questions below
Cu(s)+2Ag+(aq)⇌Cu2+(aq)+2Ag(s)Cu(s)+2Ag^+(aq)⇌Cu^{2+}(aq)+2Ag(s) Spontaneous; E = 0.46 V
Cu(s)+Pb2+(aq)⇌Cu2+(aq)+Pb(s)Cu(s)+Pb^{2+}(aq)⇌Cu^{2+}(aq)+Pb(s) Non-Spontaneous; E = -0.47 V
For a reaction with a negative ΔGo value, which of the following statements is/are FALSE?
1. The equilibrium constant K is greater than one.
2. The reaction is spontaneous when all the reactants and products are in their standard states.
Gibbs free Energy: Equilibrium
At 699 K, Δ\DeltaGo = -23.25 kJ for the reaction H2 (g) + I2 (g) ⇌ 2 HI (g). Calculate Δ\DeltaG for this reaction if the reagents are both supplied at 10.0 atm pressure and the product HI is at 1.00 atm
pressure.
Gibbs Free Energy
Determine the value of K for these reactions
Gibbs Free Energy: Formation
The value of ΔGo for the following reaction is -2745 kJ. Use this value and the information on the Data Sheet to calculate the standard free energy of formation, ΔGfo of C4H10 (g) in kJ/mol.
C4H10 (g) + 13/2 O2 (g) →\rightarrow 4 CO2 (g) + 5 H2O (l)
ΔGfo (CO2(g)) = -394.4 kJ/mol ΔGfo (H2O(l)) = -237.13 kJ/mol