22.2 Enthalpy changes in solution

Question 1

Standard enthalpy change of solution

Answer 1

Enthalpy change that takes place when one mole of a solute dissolves in a solvent

Question 2

What happens in aqueous ions?

Answer 2

Delta negative oxygen atom is attracted to the positive ion
Delta positive hydrogen atom is attracted to the negative ion

Question 3

Experimental determination of enthalpy change of solution

Answer 3

1) Weigh out sample of ionic compound
2) Pour measured volume of distilled water into a cup within a beaker
3) Quickly tip all of ionic compound into the water. Stir with thermometer until all of KCl has dissolved and temperature stays constant
4) q= m x SHC x temperature change
mass of ionic compound + water
5) Work out mols of ionic compound and divide energy by that amount

Question 4

Dissolving process

Answer 4

When a solid ionic compound dissolves in water..
-ionic lattice breaks up
-water molecules are attracted to, and surround the ions

Question 5

Enthalpy change of hydration

Answer 5

Enthalpy change that accompanies the dissolving of gaseous ions in water to form one mole of aqueous ions