This question is about reactions of metals - AQA - GCSE Chemistry Combined Science - Question 1 - 2019 - Paper 1

1. Mass of the metal added to the reaction.

2. Concentration of hydrochloric acid.

The independent variable in this reaction is the type of metal used.

Beryllium is less reactive than magnesium.

Reason: This is due to its position in the periodic table; beryllium is located in Group 2, above magnesium, and has a greater effective nuclear charge, requiring more energy to remove its outer electrons.

To calculate the concentration, use the formula:

$ext{Concentration} = \frac{\text{mass (g)}}{\text{volume (dm}^3\text{)}}$

1. Convert 50 cm³ to dm³: $50 \text{ cm}^3 = 0.05 \text{ dm}^3$
2. Substitute into the formula: $\text{Concentration} = \frac{3.2 \text{ g}}{0.05 \text{ dm}^3} = 64 \text{ g per dm}^3$