At what temperatures will the following be spontaneous?
C5H12(g) + 8O2(g) → 5CO2(g) + 6H2O(g)
ΔH°= ?
N2 (g) + 3H2(g) → 2NH3(g)
ΔH°= -92 kJ/mol
2C(graphite) + 2H2(g) → C2H4(g)
ΔH°= 52 kJ/mol
I2(g) → 2I(g)
ΔH°= ?
2NH4NO3(s) → O2(g) + 2N2(g) + 4H2O(g)
ΔH°= -236 kJ/mol
The ΔS° accompanying the conversion of solid rhombic sulfur to its monoclinic form is 1.09 J/mol·K
at 95.5°C. What is ΔH° for this transition?
What is ΔS° for the freezing of water at 1 atm pressure?
ΔH°fus = 6.02 kJ/mol
What is ΔH°vap for Br2(l)? Use this value to estimate the normal boiling point for Br2(l).
Calculate ΔS° at 25°C for the following reactions:
2NO(g) + O2(g) → 2NO2(g)
ΔS°=
N2 (g) + 3H2(g) → 2NH3(g)
ΔS°=
For the following reaction, ΔS°= 138.5 J/K. What is S° for N2O3?
2N2O3(g) → 3O2(g) + 2N2(g)
Calculate ΔG° at 298 K for each of the following using the information provided, or some other
means:
2NO(g) + O2(g) → 2NO2(g)
ΔH°= -114.1 kJ, ΔS°= -146.5 J/K
4Fe(s) + 3O2(g) → 2Fe2O3(s)
ΔH°= -1648 kJ, ΔS°= -549.3 J/K
N2 (g) + 3H2(g) → 2NH3(g)
2C(graphite) + 2H2(g) → C2H4(g)
The decomposition of isopropanol has an equilibrium constant of 0.444 at 452 K.
(CH3)2CHOH(g) → (CH3)2CO(g) + H2(g)
Kp= 0.444
@
452 K
What is ΔG° for this reaction at 452 K? Is this reaction spontaneous at 298 K?
What is ΔG at 452 K for this reaction if all gases are present at a pressure of 0.1 atm? Is the
reaction spontaneous under these conditions?
At what temperature can the following equilibrium be established?
H2O(l)  H2O(g, 0.50atm)
What is the equilibrium constant for the following reaction at 25°C?
Mg(OH)2(s) + 2H+(g)  Mg2+(g) + 2H2O(l)
Estimate the normal boiling point of pentane using the following information:
C5H12(l)
ΔH°f = -173.5 kJ/mol
C5H12(g)
ΔH°f = -146.9 kJ/mol
Estimate ΔG° for this process at 298 K.
What are ΔG and ΔG° for this process at its normal boiling point?
Using the following information at 298 K:
ΔG° (kJ/mol)
N2 (g) + 3H2(g) → 2NH3(g)
-33.0
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l)
-1010.5
N2 (g) + O2(g) → 2NO(g)
-173.1
N2 (g) + 2O2(g) → 2NO2(g)
-102.6
2N2 (g) + O2(g) → 2N2O(g)
208.4
What are ΔG° for the following?
a) N2O (g) + O2(g) → 2NO2(g)
ΔG°=?
b) 2H2 (g) + O2(g) → 2H2O(l)
ΔG°=?
c) 2NH3 (g) + 2O2(g) → N2O(g) + 3 H2O(l)
ΔG°=?
Which of these reactions will go essentially to completion under standard conditions at 298 K?
Which of these reactions will reach an equilibrium with significant amounts of products and
reactants remaining?
A possible reaction for converting methanol to ethanol is:
CO(g) + 2H2(g) + CH3OH(g) → C2H5OH(g) + H2O(g)
At 25°C:
ΔG°= -227.4 J/mol.K
ΔH°= -165.7 kJ/mol
ΔG°= -97.9 kJ/mol
Is this reaction favored at high or low temperatures? Pressures?
Estimate Kp for this reaction at 750 K