Lattice Enthalpy

Question 1

What does an ionic lattice consist of?

Answer 1

oppositely charged ions held together by strong electrostatic forces between them

Question 2

What are the properties of an ionic lattice?

Answer 2

soluble in water
conducts electricity when dissolved or molten
high mp

Question 3

why does an ionic lattice have a high mp?

Answer 3

There are strong electrostatic forces of attraction between the particles

Question 4

Why does an ionic lattice conduct electricity?

Answer 4

The ions can act as mobile charge carriers when they are not fixed within the lattice.

Question 5

Why is an ionic lattice soluble in water?

Answer 5

The polar nature of water molecules allows bonding interactions between the charged ions and the water molecules.

Question 6

What is the definition of lattice enthalpy?
(deltaLEH)

Answer 6

the formation of 1 mol of an ionic lattice from gaseous ions.
e.g Na+(g) + Cl-(g) → NaCl (s)

Question 7

What is LE a measure of?

Answer 7

the strength of the ionic bond

Question 8

What is enthalpy formation?

Answer 8

the enthalpy change when 1 mole of a
compound is formed from its elements (Na (s) + ½ Cl2 (g) → NaCl(s)

Question 9

What is lattice dissociation enthalpy?

Answer 9

the lattice enthalpy for NaCl is – 781 kJmol-1, then the energy needed to break down the lattice into its gaseous ions is the opposite, +781 kJmol-1.

Question 10

What theoretical steps are imagined to take place during the formation of a lattice from its elements?

Answer 10

-atomisation of metal
-ionisation of metal
atomisation of non metal
-electron affinity
-LEH
-deltaFH

Question 11

What is atomisation of metal?

Answer 11

-This is the energy change when 1 mole of gaseous atoms are formed from the
element in its standard state.

Question 12

What is first ionisation energy (ionisation or metal)?

Answer 12

the energy change when 1 mole of gaseous atoms loses 1 electron to
become 1 mole of gaseous unipositive ions.

Question 13

what is the atomisation of a non metal?

Answer 13

Here free gaseous atoms of the non-metal are formed

Question 14

What is electron affinity?

Answer 14

The energy change when 1 mole of atoms gain 1 mole of electrons in the gaseous state (can be first or second)

Question 15

What does it mean if something is x2 in the table?

Answer 15

then another enthalpy change relating to the element must also be doubled