Thermochemistry

Question 1

These conditions are 298K, 1atm, and 1M, and are NOT the same thing as STP

Answer 1

Standard conditions

Question 2

It’s symbol is ΔH, and it refers to the amount of heat in a reaction, with negative being exothermic and positive behind endothermic

Answer 2

Standard enthalpy

Question 3

It’s symbol is ΔS, and it refers to the amount of chaos or the spread of molecules in a reaction

Answer 3

Standard entropy

Question 4

It’s symbol is ΔG, and it refers to the amount of energy released in the conversion of reactants to products

Answer 4

Standard free energy change

Question 5

What is the difference between a state process and a process function?

Answer 5

A state function describes a system in equilibrium, but doesn’t describe the pathway it took to get there (ex: density, pressure, Gibbs free energy)

A process function describes the pathway a reaction takes from 1 equilibrium state to another (ex: heat and work)

Question 6

According to Hess’s Law, changes in enthalpy are _____, so no matter what path a reaction takes, it will end up with the same change in enthalpy

Answer 6

Additive

Question 7

What is the equation for Gibbs free energy? (at standard conditions)

Answer 7

ΔG=ΔH-TΔS

Question 8

Gibbs free energy outcomes:

ΔH +
ΔS +

Answer 8

Spontaneous only at high temps

Question 9

Gibbs free energy outcomes:

ΔH +
ΔS -

Answer 9

Nonspontaneous at all temps

Question 10

Gibbs free energy outcomes:

ΔH -
ΔS +

Answer 10

Spontaneous at all temps

Question 11

Gibbs free energy outcomes:

ΔH -
ΔS -

Answer 11

Spontaneous at low temps

Question 12

A reaction is spontaneous if ΔG is _____ and non spontaneous if ΔG is ____

Answer 12

Negative

Positive

Question 13

Equation for Gibbs free energy at non-standard conditions

Answer 13

ΔGrxn= ΔG+RTlnQ