Predict the entropy change (positive/negative) in the following:

Options

A. A liquid substance crystallises into a solid
B. Temperature of a crystal is increased
C. `CaCO_(3)(s) rarr CaO(S) +O_(2)(g)`
D. `N_(2)(g)(1atm) rarr N_(2)(g) (0.5 atm)`

Explanation

To predict the entropy change (ΔS) in the given scenarios, we will analyze each situation based on the principles of thermodynamics, specifically focusing on the concept of randomness or disorder in a system.

### Step-by-Step Solution:

1. **Liquid Crystallizing into a Solid:**
- When a liquid substance crystallizes into a solid, the particles in the solid are arranged in a more ordered structure compared to the liquid state.
- **Entropy Change (ΔS):** Since the disorder decreases, ΔS is **negative**.

...