Lesson 10 - Thermodynamics Cont. (Gibbs)

Question 1

Enthalpy (H)

Answer 1

How much heat is taken in or given off by a system.

Question 2

Heat (q)

Answer 2

Exchange of thermal energy due to a temperature difference.

Question 3

Thermal Energy

Answer 3

The total of all kinetic energies within a given system.

(energy in an object or system due to the movement of its molecules and atoms).

Question 4

Delta S Fusion Equation

Answer 4

∆S = ∆Hf / T

Question 5

Temperature (Definition)

Answer 5

Measure of the average kinetic energy of the atoms or molecules in the system.

Question 6

Gibbs Free Energy (Def)

Answer 6

Energy that is available (free) to do work.

Question 7

Gibbs Free Energy Equation
“Get Higher Test Scores”

Answer 7

ΔG° = ΔH° - TΔS°
or
ΔG = ΔH - TΔS

Question 8

Gibbs Free Energy (Standard free energies formation equation) Alternate method from ΔG° formation.

Answer 8

ΔG° = (Sum ΔG° products) - (Sum ΔG° reactants)

Question 9

ΔG° < 0

Answer 9

Spontaneous (free energy in system used for reaction).

Question 10

ΔG° > 0

Answer 10

Nonspontaneous (Outside energy used)

Question 11

ΔG° = 0

Answer 11

Equilibirum

Question 12

Dealt S Vaporization Equation

Answer 12

delta S (vap) = delta H (vap) / T(boiling point in K).

Question 13

In a spontaneous process at constant temp and pressure, the free energy always

A. Increases
B. Decreases

Answer 13

B. Decreases - spontaneous processes use up their free energy.

Question 14

Spontaneous Reactions are more likely to be?

A. Exothermic (ΔH < 0)
B. Endothermic (ΔH > 0)

Answer 14

Exothermic - they result in a decrease ΔH < 0 of the systems overall energy.

Question 15

ΔG scenario(s) when:

ΔS > 0 and ΔH > 0 (endothermic)

Answer 15

ΔG < 0 - at high temps.

Question 16

ΔG scenario(s) when:

ΔS < 0 and ΔH > 0 (endothermic)

Answer 16

ΔG > 0 - at ANY temp.

Question 17

ΔG scenario(s) when:

ΔS > 0 and ΔH < 0 (exothermic)

Answer 17

ΔG < 0 - at ANY temp.

Question 18

ΔG scenario(s) when:

ΔS < 0 and ΔH < 0 (exothermic)

Answer 18

ΔG < 0 - at low temps.

Question 19

Gibbs Free Energy Equilibrium (Non-Standard) Equation. (Find ΔG)

Answer 19

ΔG = ΔG°+ RT*ln(Q)

Question 20

Gibbs Free Energy (Standard Conditions Equation) at Equilibrium

Answer 20

ΔG° = -RT*ln(keq)

Question 21

Gibbs Free Energy (Nonstandard Conditions) Definition.

Answer 21

Instantaneous difference in free energy between the reactants and products.

Question 22

Reaction Quotient (Q) Definition

Answer 22

Ratio of units for the concentrations or pressure of the products over the reactants at a specific point of time.

Question 23

Keq (Definition)

Answer 23

Ratio of units for the concentrations of the products over the reactants at equilibrium.

Question 24

If ΔG < 0 what is Keq and which way is the reaction going?

Answer 24

Keq > 1
The reaction goes forward.
(More products than reactants at equilbrium).

Question 25

If ΔG = 0 what is Keq and which way is the reaction going?

Answer 25

Keq = 1 The reaction is at equilibrium.

Question 26

If ΔG > 0 what is Keq and which way is the reaction going?

Answer 26

Keq < 1 The reaction is going in the reverse direction. (to the left - more reactant favored and not spontaneous)

Question 27

Keq Equation (how to calculate Keq)

Answer 27

Keq = e^-(ΔG/RT)

Question 28

ΔG and ΔH Units

Answer 28

Kj/Mol

Question 29

ΔS Unit

Answer 29

J/mol

Question 30

Standard Conditions for (gasses, solutions, and temperature)

Answer 30

(Gasses) = 1atm (Solutions) = 1M Temp = 25c or 298.15

Question 31

Room Temperature in C and K

Answer 31

25c and 298.15k

Question 32

When to use ΔG = ΔG°+ RT*ln(Q)

Answer 32

When you want to see if the concentration of the products and reactants are products favored (favored in the forward direction). - Spontaneous.