Given the equation representing a phase change for carbon dioxide, CO2(s):CO2(s) + energy → CO2(g)Which statement describes this phase change in terms of energy and entropy?

Regents Chemistry Exam January 2025 Question 43

43 Given the equation representing a phase change

for carbon dioxide, CO2(s):CO2(s) + energy → CO2(g)

Which statement describes this phase change in terms of energy and entropy?

(1) The phase change is endothermic and entropy increases.

(2) The phase change is endothermic and entropy decreases.

(3) The phase change is exothermic and entropy increases.

(4) The phase change is exothermic and entropy decreases.

Solution:

Entropy represents disorder. Gases (g) are more disordered than solids(s) which means entropy increases in this phase change. Going from solid to gas requires an input of energy which means the phase change is endothermic. Choice 1 is the correct answer.

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