This question is about elements in group 7, the halogens - Edexcel - GCSE Chemistry Combined Science - Question 4 - 2022 - Paper 1

The word equation for the reaction is:

Iron + Chlorine → Iron Chloride

The most reactive halogen with iron in Figure 6 is chlorine.

To find the mass of iron and chlorine, we can use the percentage given:

1. Calculate the mass of iron:

   $\text{Mass of iron} = \frac{34.4}{100} \times 125 = 43 g$

2. To find the mass of chlorine:

   $\text{Mass of chlorine} = 125 - \text{Mass of iron} = 125 - 43 = 82 g$

The correct words to complete the sentences are:

1. a catalyst
2. lower

The iron chloride speeds up the reaction because it is a catalyst. After the reaction, the mass of iron chloride is unchanged.