Enthalpies Of Solution And Hydration

Question 1

What is the enthalpy change of lattice formation?

Answer 1

The enthalpy change when 1 mole of solid ionic compound is formed from its gaseous ions under standard conditions

Question 2

What is the enthalpy change of lattice dissociation?

Answer 2

The enthalpy change when 1 mole of a solid ionic compound is completely dissociated into its gaseous ions under standard conditions

Question 3

What is the enthalpy change of hydration?

Answer 3

Enthalpy change when one mole of aqueous ions is formed from gaseous ions

Question 4

What is the enthalpy change of solution?

Answer 4

The enthalpy change when 1 mole of an ionic substance dissolves in enough so,vent to for an infinitely dilute solution

Question 5

What is Hess’s law?

Answer 5

The total enthalpy change of a reaction is always the same no matter the route taken

Question 6

Enthalpy of solution equation:

Answer 6

NaCl(s) to Na+(aq)+Cl-(aq)

Question 7

How is the Hess cycle for enthalpy of solution constructed?

Answer 7

First arrow going down (lattice of dissociation)

Following arrows up (enthalpy of hydration)

Question 8

What is enthalpy of solution equal to?

Answer 8

Lattice dissociation+ hydration

Question 9

Lattice enthalpy dissociation:

Answer 9

Positive bc it’s endothermic

Question 10

Enthalpy hydration in a solution Hess cycle:

Answer 10

Negative because forming bonds releases energy

Exothermic

Question 11

Enthalpy cycle is used for solution and hydration

Answer 11

Not a Hess cycle
Arrows underneath go in the same direction
First set go down
The second go up

Question 12

How does ion size impact the reaction?

Answer 12

Higher charged ions have a larger charge density
So a stronger attraction between H2O and ion
So larger hydration enthalpy
If ion charges are the same, the smaller molecule has a greater change density