Theoretical And experimental lattice enthalpy

Question 1

What do difference in values of experimental and lattice enthalpies depend on

Answer 1

How purely ionic a substance is

Question 2

How can theoretical lattice models be calculated

Answer 2

Perfect ionic model

Question 3

What is a perfect ionic model

Answer 3

lons that are perfectly spherical

The charge is evenly distributed
in this sphere (point charges)

Question 4

What does the lattice enthalpy and theoretical lattice being different show

Answer 4

This tells us that the compound
being experimented on doesn’t
follow the perfectly ionic model

and has come covalent characteristics

Question 5

More polarisation

Answer 5

The more polarisation we get,

the more covalent character there will be

Question 6

Positive ion

Answer 6

Most of the time the positive ion
distorts the charge distribution in
the negative ion.

We say the positive ion polarises the negative ion.

Question 7

Its experimental value higher or is theoretical higher

Answer 7

Experimental

Question 8

What does the experimental value being higher show

Answer 8

have some covalent character being displayed.

This is caused by larger distortions in the negative ion.

Question 9

The bigger the difference in lattice enthalpy ll

Answer 9

The bigger the difference in lattice enthalpy the more polarisation you have the greater the covalent character.

Question 10

What can lattice enthalpy show

Answer 10

How much a substance is purely ionic

Question 11

For a substance to dissolve

Answer 11

Substance bonds must
break (endothermic)

New bonds formed
between the solvent and substance (exothermic)