This question is about metals and the reactivity series - AQA - GCSE Chemistry - Question 2 - 2020 - Paper 1

The pale grey crystals observed are silver, which forms when copper displaces silver from the silver nitrate solution. The blue solution indicates the presence of copper ions, which are produced during the reaction.

This shows that silver is less reactive than copper because copper can displace silver from its compound, indicating that copper is more reactive.

1. Add the metals (magnesium, iron, copper) separately to dilute hydrochloric acid.

2. Observe the reactions:

   • For copper, expect no reaction if it is the least reactive.
   • Magnesium should react vigorously, producing bubbles and heat.
   • Iron should react moderately, producing some bubbles but less than magnesium.

3. Control variables:

   • Use the same concentration and volume of hydrochloric acid.
   • Use the same mass of each metal.
   • Ensure the same particle size of the metals.
   • Maintain the same temperature of all solutions.

The output will help identify the order of reactivity based on the extent and speed of the reactions.

To calculate the relative atomic mass of metal M:

$ext{A}_r = \frac{(203 \times 30) + (205 \times 70)}{100}$

Calculating:

$=(6090 + 14350) / 100$

$= 204.4$

Thus, the relative atomic mass (A_r) of metal M is 204.4.