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

Question 4

Fertilisers are formulations. 04.1 What is a formulation? A formulation is a mixture designed as a useful product. 04.2 A bag of fertiliser contains 14.52 kg of... show full transcript

Worked Solution & Example Answer:Fertilisers are formulations - AQA - GCSE Chemistry: Combined Science - Question 4 - 2018 - Paper 2

Step 1

What is a formulation?

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Answer

A formulation is a mixture designed as a useful product.

Step 2

Calculate the number of moles of ammonium nitrate in the bag of fertiliser.

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Answer

To calculate the number of moles, use the formula:

$ext{Number of moles} = \frac{\text{mass}}{\text{molar mass}}$

Here, mass = 14.52 kg = 14520 g and molar mass of ammonium nitrate (NH₄NO₃) = 80 g/mol.

Thus,

$ext{Number of moles} = \frac{14520 \, \text{g}}{80 \, \text{g/mol}} = 181.5 \, \text{mol}$

Converting to standard form, this is approximately: $1.8 \times 10^{2} \text{ mol}$ .

Step 3

Explain why potassium chloride has a high melting point.

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Answer

Potassium chloride (KCl) has a high melting point due to its ionic bonding structure.

In an ionic lattice, the strong electrostatic forces of attraction between the positively charged potassium ions (K⁺) and negatively charged chloride ions (Cl⁻) require a large amount of energy to break. This strong interaction leads to a high melting point, as the lattice structure must overcome these forces to transition to a liquid state.

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