This question is about iron - AQA - GCSE Chemistry Combined Science - Question 8 - 2018 - Paper 1

Any unreacted iron can be separated from the mixture through filtration or by using a magnet.

To calculate the mass of iron produced from the reaction of magnesium with iron chloride, follow these steps:

1. Calculate the number of moles of magnesium: $\text{Moles of Mg} = \frac{0.120 \text{ g}}{24 \text{ g/mol}} = 0.005 \text{ moles}$

2. Use the stoichiometry of the reaction. From the equation, 3 moles of Mg produce 2 moles of Fe: $\text{Moles of Fe} = 0.005 \text{ moles Mg} \times \frac{2 \text{ moles Fe}}{3 \text{ moles Mg}} = 0.00333 \text{ moles Fe}$

3. Calculate the mass of iron produced: $\text{Mass of Fe} = 0.00333 \text{ moles} \times 56 \text{ g/mol} = 0.1866 \text{ g} = 186.6 \text{ mg}$

Thus, rounding gives about 187 mg of iron produced.

In this reaction, iron (III) ions ( ext{Fe}^{3+}) are the species that are reduced. The half equation for the reduction can be written as:

$\text{Fe}^{3+} + 3e^- \rightarrow \text{Fe}$

This indicates that iron ions gain electrons to form solid iron.