Question

which substance will have the greatest standard molar entropy value? h₂o(s) rn(g) br₂(l)

Explanation:

Step1: Recall entropy trends

Entropy (disorder) order: gas > liquid > solid. Also, for gases, larger/more complex molecules (or atoms with more electrons) have higher entropy due to more microstates.

Step2: Analyze each substance

• $\ce{H2O(s)}$: solid (lowest entropy among states).
• $\ce{Rn(g)}$: gas. Rn is a noble gas with many electrons (large atomic size), so more microstates.
• $\ce{Br2(l)}$: liquid (entropy < gas).

Step3: Compare entropies

Gas state (Rn) has higher entropy than liquid (Br₂) and solid (H₂O). Among gases, Rn's large size gives more disorder.

Answer:

Rn(g)