Question

Predict how the entropy of the substance is affected in the following processes?

a) Ar(l) yields Ar(g)
entropy? increases,decreases or stays the same
b) Br₂ (l, 1 bar, 25 degrees celcius) yields Br₂ (g, 1 bar, 25 degrees Celsius)
entropy? increases,decreases, or stays the same.
c) CO₂(g) yields CO₂(s)
entropy? increases,decreases, or stays the same

Answer 1

The entropy increases when argon goes from liquid to gas and when bromine goes from liquid to gas, due to the higher disorder in the gaseous state. Conversely, entropy decreases when carbon dioxide transitions from gas to solid, as the solid state is more ordered.

Step-by-step explanation:

In the context of entropy changes for certain processes:

• Argon transition from liquid to gas (Ar(l) → Ar(g)): The entropy increases. This is because gases have more disorder and more possible arrangements of particles compared to liquids.
• Bromine transition from liquid to gas (Br₂(l) → Br₂(g)): Similarly, the entropy increases for the same reasons as argon; transitioning from a liquid to a gas state introduces more disorder.
• Carbon dioxide transition from gas to solid (CO₂(g) → CO₂(s)): The entropy decreases. The solid state of a substance is more ordered than the gaseous state, thus reducing entropy.

Several concepts affect entropy changes:

• Entropy typically increases when a substance transitions from a solid or liquid to a gas.
• A rise in temperature generally leads to an increase in entropy due to higher kinetic energy and disorder among particles.
• Phase transitions from solid to liquid, or liquid to gas, also result in an increase in entropy due to higher dispersal of matter.
• Moreover, processes that result in a greater number of product molecules compared to reactant molecules usually exhibit an increase in entropy, especially if the products are in the gaseous state.