Answered

At Westonci.ca, we connect you with the answers you need, thanks to our active and informed community. Get detailed and precise answers to your questions from a dedicated community of experts on our Q&A platform. Experience the ease of finding precise answers to your questions from a knowledgeable community of experts.

Which of the following choices would have a negative entropy change?

A. [tex]N_2(g) + 3H_2(g) \rightarrow 2NH_3(g)[/tex]

B. [tex]Fe_2O_3(s) + 3C(s) \rightarrow 2Fe(s) + 3CO(g)[/tex]

C. [tex]CaCO_3(s) \rightarrow CaO(s) + CO_2(g)[/tex]

D. [tex]H_2O(s) \rightarrow H_2O(l)[/tex]

Sagot :

GinnyAnswer
To determine which of the given reactions would have a negative entropy change, we need to consider whether the entropy (disorder) of the system increases or decreases during each reaction. Entropy generally increases when a reaction produces gases from solids or liquids and decreases when gases are converted into fewer gas molecules or into solids or liquids.

Let’s analyze each reaction step-by-step:

### A. [tex]\( N_2(g) + 3 H_2(g) \to 2 NH_3(g) \)[/tex]

- Reactants: 1 mole of [tex]\( N_2 \)[/tex] gas and 3 moles of [tex]\( H_2 \)[/tex] gas, for a total of 4 moles of gas.
- Products: 2 moles of [tex]\( NH_3 \)[/tex] gas.
- Comparison: We start with 4 moles of gas and end with 2 moles of gas.
- Entropy Change: The number of gas molecules decreases, which means the disorder of the system decreases. Therefore, the entropy decreases.

### B. [tex]\( Fe_2O_3(s) + 3 C(s) \to 2 Fe(s) + 3 CO(g) \)[/tex]

- Reactants: 1 mole of [tex]\( Fe_2O_3 \)[/tex] solid and 3 moles of carbon solid, for a total of 4 moles of solid.
- Products: 2 moles of iron solid and 3 moles of [tex]\( CO \)[/tex] gas.
- Comparison: We start with solids only and produce some gas.
- Entropy Change: Solid to gas conversion increases disorder. Therefore, the entropy increases.

### C. [tex]\( CaCO_3(s) \to CaO(s) + CO_2(g) \)[/tex]

- Reactants: 1 mole of [tex]\( CaCO_3 \)[/tex] solid.
- Products: 1 mole of [tex]\( CaO \)[/tex] solid and 1 mole of [tex]\( CO_2 \)[/tex] gas.
- Comparison: We start with a solid and produce a gas.
- Entropy Change: The formation of a gas from a solid increases disorder. Therefore, the entropy increases.

### D. [tex]\( H_2O(s) \to H_2O(l) \)[/tex]

- Reactants: 1 mole of [tex]\( H_2O \)[/tex] solid (ice).
- Products: 1 mole of [tex]\( H_2O \)[/tex] liquid (water).
- Comparison: We start with a solid and produce a liquid.
- Entropy Change: Solids are more ordered than liquids, so converting a solid to a liquid increases disorder. Therefore, the entropy increases.

### Conclusion:

By analyzing each reaction, we observe that only reaction A ([tex]\( N_2(g) + 3 H_2(g) \to 2 NH_3(g) \)[/tex]) has a decrease in the number of gas molecules, leading to a decrease in entropy. Therefore, the reaction with a negative entropy change is:

A. [tex]\( N_2(g) + 3 H_2(g) \to 2 NH_3(g) \)[/tex]
We appreciate your time on our site. Don't hesitate to return whenever you have more questions or need further clarification. We appreciate your time. Please revisit us for more reliable answers to any questions you may have. Find reliable answers at Westonci.ca. Visit us again for the latest updates and expert advice.