GCSE Chemistry Coursework

An investigation of how the concentration of hydrochloric acid affects the rate of reaction between hydrochloric acid and potassium carbonate K₂Co₃₍₃₎ + HCl --- KCl_(0.9) + H₂O(1)+Co₂₍₉₎

Plan:

Introduction

Aim

Independent variables

Equipment

Prediction

Method

Results

Analysing evidence

Evaluation

Introduction:

In my coursework I’m going to investigate the rates of reaction, and the effect different changes have on them. The rate of reaction is the rate of loss of a reactant or the rate of formation of a product during a chemical reaction. There are five factors which affect the rate of a reaction, according to the collision theory of reacting particles: temperature, concentration of solution, pressure, surface area, and catalysts. I have chosen to investigate the effect of the concentration of hydrochloric acid on the rate of reaction. I’ve chosen this factor, because it would be easier to measure the concentration of hydrochloric acid and get more accurate results in my experiment.

Aim:

To investigate how the concentration of hydrochloric acid affects the rate of a reaction between hydrochloric acid and potassium carbonate.

Using my preliminary experiments I decided on using the following equipment:

1. Measuring cylinder

2. Stop clock

3. Measuring tube

4. Stick

5. Scales

Also I used following chemical components:

1. Potassium

2. Hydrochloric acid^-3

Prediction: If I double the concentration of hydrochloric acid, the rate of reaction will double or time will halve. If it won’t halve, I predict that if I increase the concentration of hydrochloric acid, the rate of reaction will increase and time taken for reaction to happen will decreases. In dilute acid, there are not so many acid particles. So there’s not much chance of an acid particle hitting a potassium atom. When the acid is more concentrated, there are more acid particles, so there’s more chance that the reaction will go faster. If solutions of reacting particles are made more concentrated there are more particles per unit volume. Collisions between reacting particles are therefore more likely to occur. For a reaction to occur particles have to collide with each other. Only particles with enough energy to overcome the barrier will react after colliding. The minimum energy that a particle must have to overcome the barrier is called the activation energy, or Ea. The size of this activation energy is different for different reactions. If the frequency of collisions is increased the rate of reaction will increase. However, the percentage of successful collisions will remain the same. An increase in the frequency of collisions can be achieved by increasing the concentration. The more successful collisions there are, the faster the reaction.

Concentration – If the concentration of a solution is increased there are more reactant particles per unit volume. This increases the probability of reactant particles colliding with each other.

Also there are some factors, which can affect the rate of reaction:

1. Temperature

2. Concentration

3. Surface area

4. Catalyst

Effect of a catalyst - A catalyst works by providing an alternative reaction pathway that has lower activation energy. Catalyst provides a reaction route of lower activation energy, however, a greater proportion of particles will have energy greater than the activation energy.