enthalpy (A2)

Question 1

What is lattice enthalpy? (🔼 LE H°)

Answer 1

Formation of 1 mole of ionic lattice from gaseous ions
used as a measure of strength of the ionic bonding in an ionic lattice

Question 2

Standard enthalpy change of atomisation (🔼at H°)

Answer 2

The enthalpy change for the formation of one mole of gaseous atoms from the element in its standard state under standard conditions

Question 3

First ionisation energy (🔼 IE H°)

Answer 3

The enthalpy change required to removed one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

Question 4

First election affinity (🔼 EA H°)

Answer 4

The enthalpy change that takes place when one electron is added to each atom in one mole of gaseous atoms to form one mole of gaseous 1- ions

Question 5

Describe the stages in a born-haber cycle

Answer 5

🔼IE/EA H°
gaseous atoms → gaseous ions |
↑. 🔼 atH° |
elements in standard states | 🔼 LE H°
↓. 🔼 f H°. V
IONIC LATTICE.

Question 6

enthalpy change of solution (🔼 solH°)

Answer 6

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

Question 7

enthalpy change of hydration (🔼 hydH°)

Answer 7

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

Question 8

describe the stages of an enthalpy cycle using hydration/solution

Answer 8

🔼 hydH°
gaseous ions → aqueous ions
|. ↑
🔼 LE H° ↑ 🔼 solH°
V. ↑
IONIC LATTICE

Question 9

what are the factors affecting lattice enthalpy?

Answer 9

ionic size (radius increases → attraction between ions decreases → LE less negative → melting point decreases)
ionic charge (ionic charge increases → attraction between ions increases → LE more negative → MP increases)

Question 10

What are the factors affecting hydration?

Answer 10

ionic size (radius increases → attraction between ions and H2O decreases → hydration energy less negative)
ionic charge (charge increases → attraction with H2O increases → hydration energy more positive)