13: Energetics II

Question 1

Standard lattice energy (ΔLEH°) definition

Answer 1

the energy change when 1 mole of an ionic lattice is formed from is gaseous ions, under standard conditions

Question 2

Stronger bonding in an ionic lattice has a __ lattice energy?

Answer 2

more negative

Question 3

Enthalpy change of hydration (ΔhydH) defintion

Answer 3

the enthalpy change when 1 mole of gaseous ions dissolves in water

Question 4

Enthalpy change of solution (ΔsolH) definition

Answer 4

the enthalpy change when 1 mole of solute dissolves in water

Question 5

Ions with a greater charge have ____ enthalpies of hydration

Answer 5

More exothermic
Greater at attracting water molecules, stronger electrostatic attraction, more energy released when the bonds are made

Question 6

Smaller ions have ____enthalpies of hydration

Answer 6

More exothermic
Higher charge density, attract water molecules better

Question 7

What is entropy?

Answer 7

A measure of disorder of a system - the number of ways that particles can be arranged and the number of ways that the energy can be shared out between them
The more disorder, the higher the entropy
Substances are more energetically stable when there’s more disorder

Question 8

Units of entropy?

Answer 8

J K-1 mol-1

Question 9

ΔS system equation?

Answer 9

ΔS system = ΔSproducts - ΔSreactants

Question 10

ΔS total equation?

Answer 10

ΔStotal = ΔSsystem + ΔSsurroundings

Question 11

ΔSsurroundings equation?

Answer 11

-ΔH / T

Question 12

Free energy equation?

Answer 12

ΔG = ΔH - TΔSsystem