Thermodynamics

Question 1

(Thermodynamics) Exothermic Reaction

Answer 1

Reaction releases energy; products have less energy than reactants. Heat is released and product feels hot. Generally favorable.

Question 2

(Thermodynamics) Endothermic Reaction

Answer 2

Reaction absorbs energy; products have more energy than reactants. Heat is absorbed and product feels cold. Generally unfavorable.

Question 3

(Thermodynamics) Favorable ΔG Value

Answer 3

ΔG < 0; negative

Question 4

(Thermodynamics) Favorable ΔS Value

Answer 4

ΔS > 0; positive

Question 5

(Thermodynamics) Favorable ΔH Value

Answer 5

ΔH < 0; negative

Question 6

(Thermodynamics) Celsius to Kelvin Conversion

Answer 6

C° + 273 = K

Question 7

(Thermodynamics) Enthalpy of a Reaction

Answer 7

ΔH = H(products) - H(reactants)

Question 8

(Thermodynamics) Bond Enthalpy

Answer 8

ΔH = ΣBE(bonds broken) - ΣBE(bonds formed)

Question 9

(Thermodynamics) Gibbs Free Energy Equation

Answer 9

ΔG = ΔΗ - ΤΔS

Question 10

(Thermodynamics) Gibbs Free Energy Trends

Answer 10

ΔG = ΔΗ - ΤΔS

|ΔG = -|ΔΗ = -|ΔS = -| Favorable at low temp.

|ΔG = -|ΔΗ = +|ΔS = +| Favorable at high temp.

|ΔG = +|ΔΗ = +|ΔS = -| Always true.

|ΔG = -|ΔΗ = -|ΔS = +| Always true.

Question 11

(Thermodynamics) Enthalpy of Reaction (ΔΗ) from Heat Transferred (Δq)

Answer 11

Δq / moles of limiting reactant = ΔΗ