Question 1
At 25°C, Δ
G°
f is -620 kJ/mol for SiCl
4(
g) and -592 kJ/mol for MgCl
2(
s). Calculate Δ
G° for the reaction, SiCl
4(
g) + 2 Mg(
s) → 2 MgCl
2(
s) + Si(
s) and determine if the reaction is spontaneous at 25°C if the pressure of SiCl
4(
g) is 1 atm.
◦ Δ
G° = 28 kJ; the process is spontaneous.
◦ Δ
G° = -564 kJ; the process is nonspontaneous.
◦ Δ
G° = -564 kJ; the process is spontaneous.
◦ Δ
G° = 28 kJ; the process is nonspontaneous.
Question 2
Which of the following are unstable with respect to their constituent elements at 25°C?

◦ C
8H
18(
l), C
2H
2(
g)
◦ C
2H
2(
g)
◦ C
8H
18(
l), CH
3OH(
l)
◦ CH
3OH(
l)