Fertilisers are formulations - AQA - GCSE Chemistry Combined Science - Question 4 - 2018 - Paper 2

Given the mass of ammonium nitrate is 14.52 kg, we first convert this to grams:

$14.52 ext{ kg} = 14,520 ext{ g}$

Next, we use the relative formula mass of ammonium nitrate, which is given as 80 g/mol. The number of moles can be calculated using the formula:

$ext{Moles} = \frac{\text{mass}}{\text{molar mass}}$

Substituting in the values:

$\text{Moles} = \frac{14,520 ext{ g}}{80 ext{ g/mol}} = 181.5 ext{ mol}$

Converting this to standard form gives:

$1.815 \times 10^{2} \text{ mol}$

Potassium chloride has a high melting point due to its ionic structure. In this structure, potassium ions (K+) and chloride ions (Cl-) form a giant lattice framework.

The attractions between the oppositely charged ions are strong and require a large amount of energy to overcome. Thus, a significant amount of heat is necessary to break these ionic bonds, resulting in a high melting point.