Question

Determine which of the following reactions at constant pressure represent surrounding that do work on the system environment 

I. 4NH₃(g) + 7O₂(g) → 4NO₂(g) + 6H₂O(g) 

II. CO(g) + 2H₂(g) → CH₃OH(l) 

III. C(s, graphite) + H₂O(g) →CO(g) + H₂(g) 

IV. H₂O(s) → H₂O(l) 

a. III, IV b. II and III c. II, IV d. I and II, IV 

Answer 1

Correct option (D) I and II, IV

Explanation:

W = -P_ext, ΔV = - Δn_gRT and Δn_g is –ve for I and II also ΔV = -ve for IV (on contraction surrounding does work on surrounding).