U2-2-2 - Entropy

Question 1

Entropy

Answer 1

A measure of the degree of disorder of a system

Question 2

Symbol for entropy

Answer 2

S

Question 3

Which has the highest entropy:

solids, liquids or gases?

Answer 3

Gases

(particles free to move = high disorder)

Question 4

Which has the lowest entropy:

solids, liquids or gases?

Answer 4

Solids

(particles can only vibrate, not move freely = low disorder)

Question 5

What happens to entropy as temperature increases?

Answer 5

Entropy increases
(more kinetic energy = more disorder)

Question 6

State the 2nd law of thermodynamics

Answer 6

The total entropy of a reaction system and its surroundings always increases for a spontaneous process.

Question 7

What is a spontaneous process?

Answer 7

A process which will happen without having to add heat.

The products are favoured at the conditions used for the reaction.

Question 8

State the 3rd law of thermodynamics

Answer 8

At 0 K the entropy of a perfect crystal is 0.

Question 9

Units for entropy (S)

Answer 9

J K^-1 mol^-1