For the reaction I2(g) → I2(s), ΔH° = -62.4 kJ at 25°C. Based on these data, at 25°C...

Question

A) ΔH°vap = -62.4 kJ/mol.

B) ΔH°vap = 62.4 kJ/mol.

C) ΔH°sub = -62.4 kJ/mol.

D) ΔH°sub = 62.4 kJ/mol.

Answer 1

Going from a solid (s) to a gas (g) is called sublimation.

The equation given is for going from a gas (g) to a solid (s), which is the reverse of sublimation and so the value of ∆H would be the same but the sign would be opposite. Thus, the correct answer would be (D).

BTW, this process (reverse of sublimation) is referred to as deposition or solidification