6 (a) A student investigated the rate of a reaction - Edexcel - GCSE Chemistry - Question 6 - 2013 - Paper 1

In Experiment 2, the concentration of sulfuric acid is higher (1.5 mol dm⁻³) compared to Experiment 1 (0.5 mol dm⁻³). A higher concentration increases the number of acid particles, leading to a greater frequency of collisions with the zinc.

Additionally, in Experiment 2, the temperature is increased to 40°C. Higher temperatures give the particles more kinetic energy, enabling them to collide with greater energy. According to collision theory, this means there will be more effective collisions that result in a reaction.

Consequently, both the increased concentration and elevated temperature in Experiment 2 contribute to a faster rate of reaction compared to Experiment 1.

The reaction of zinc with copper sulfate is a displacement reaction.

This type of reaction occurs when a more reactive element displaces a less reactive element from its compound.

In an exothermic reaction, the energy of the products is lower than that of the reactants. On the diagram:

• Draw a horizontal line representing the energy of the reactants.
• Draw another line lower than the reactants to represent the products, showing that energy has been released in the reaction.