Investigating the effect of changing the concentration of acid on the rate of reaction of Magnesium and Hydrochloric acid.

Aim – the investigation will test whether changing the concentration of Hydrochloric acid has an effect on the rate of reaction when it is added to a strip of Magnesium.

Prediction – I predict that the rate of the reaction will increase as the concentration of the Hydrochloric acid is increased. I have made this prediction based on my knowledge of the collision theory. This theory states that when there is a higher concentration of something, there will be more particles of that object in the same area (see diagram below). Therefore the particles will have less space to move around, and increase the number of collisions. All the variables in the experiment all relate to the collision theory in some way

In this experiment, there are many variables, but the concentration of acid is the only variable that we will change. All the other variables will be kept constant. The 3 variables that will be kept constant are the surface area, the temperature and the omission of any catalyst.

The temperature must be kept constant, because any increase or decrease in the temperature will have an effect on the rate of the reaction. This is because, if the temperature is higher, (to a certain point) this will give more energy to the particles, making them move around faster, thus increasing the number of collisions. To make sure the temperature is kept constant, the temperature will be checked at various times during the experiment.

A catalyst will not be used in this experiment, as this would affect the rate of reaction. This is because a catalyst provides a site for 2 molecules to meet and bond, thus speeding up the reaction.

The surface area is the last variable that will be kept constant throughout the experiment. If the surface area of the Magnesium strip is increased, this will cause an increase in the rate of reaction. This is because the larger the surface area, the more atoms there are for the particles to collide with. To keep the surface area constant, the Magnesium ...