Chem Entropy Test

Unit for entropy

J/K (energy dispersion per temperature)

Definition of Entropy

Number of possible microstates 

Concept of Entropy

A measure of randomness (chaos, disorder, etc)

Microstates Definition

Specific configurations of a system considering position & energy.

More microstates means…

More entropy

Highest kinetic and potential energy (gases) means what to entropy?

Most entropy

Least kinetic and potential energy (solids) means what to entropy?

Least entropy

PE definition

How far apart particles are in the substance

Increasing amt. of moles does what to entropy of a system?

Delta S system will be positive

How much influence does the number of moles have on entropy?

Moderate influence.

What has more entropy, mixtures or non-mixtures?

Mixtures

How large is the influence on entropy from mixtures/nonmixtures?

Moderate influence

What effect does phase change (excluding gas) have on entropy? How strong is the influence?

Phase change left to right increaes entropy and the influence is moderate.

More complex molecules have more/less entropy?

More entropy

How impactful is the complexity of molecules on entropy?

Least impactful

How does the sign of Hsystem compare to Hsurroundings?

They are opposite

How does the sign of Hsurroundings compare to Ssurroundings?

They have the same sign

What is the main factor when determining the surroundings’ entropy and why?

Energy is the main factor because the space of the surroundings can not be determined as it is always expanding and contracting.

What is the second law of thermodynamics?

The entropy of the universe is always increasing. The total change in entropy of the universe is always positive.

When is a process spontaneous?

When it agrees with 2LT by increasing the entropy of the universe.

When is a process not spontaneous?

When it disagrees with 2LT by taking away from the entropy of the universe.

What will happen when a spontaneous reaction is started and why?

Once activation energy is met, it will continue until completion. This is because spontaneous reactions don’t require a constant source of energy.

Why do spontaneous reactions happen the way they do?

Systems have a natural tendency to move toward a state of greater disorder and energy disperal.

What is the sign of delta s universe for a spontaneous reaction?

Positive

What is the sign of delta s universe for a not spontaneous reaction?

Negative

What does delta s universe refer to?

The observed process’ contribution to the entropy of the Universe