Lecture 20-22

Question 1

Change in system’s internal energy formula

Answer 1

delta (E) = q + w
- delta (E) —> change in internal energy
- q —> heat
(-) if loses heat
(+) if gains heat
- w —> work
(-) if work done by the system (ex: expanding makes it lose energy)

Question 2

What is the formula for work using P and V

Answer 2

w = -P (delta) V

Question 3

What is entropy

Answer 3

• Chaos
• Measure of randomness
• Measure of diff positional probabilities

Question 4

What makes a reaction spontaneous (in regards to entropy)

Answer 4

When the entropy is higher, the reaction is more spontaneous

Question 5

Why does gas have a higher entropy than liquid

Answer 5

More positional probabilities (more positions they can take up)

Question 6

What is the formula for entropy and how do you know if a process is spontaneous using it

Answer 6

delta (S) univ = delta (S) sys + delta (S) surr

If delta (S) univ is +, SPONTANEOUS
—> only way for smth to be spontaneous is for the entropy to increase

Question 7

What is delta (S) surr and formula

Answer 7

quantity of heat (delta H)/ temperature (K)

—> sign is dependant on heat flow
(exo process): into of surr (delta S surr positive)
(endo process) out of surr (delta S surr negative

delta H
+ heat flows into system
- heat flows out of system

delta (S) surr = - delta (H)/T

Question 8

What is free energy and what is the equation

Answer 8

G (tells if reaction is going right or left)

delta (G) = delta (H) - T delta (S) sys

delta (S) univ = -delta (G)/T