The aim of this investigation is to find out the effect of varying the concentration of acid, in the reaction between dilute hydrochloric acid and magnesium ribbon. The rate of a chemical reaction is a measure of how fast the reaction takes place.
The factors that could affect the rate of reaction in my experiment are as follows:.
Concentration of acid- this could affect the rate of reaction because the higher the concentration of the acid, the more acid particles, so more collisions per second therefore there will be more successful collisions per second.
Temperature of the acid- if the starting temperature of the acid is warmer each time, the speed at which the acid particles collide with the magnesium ribbon will increase.
Surface area of the magnesium- If the magnesium has a greater surface area each time the experiment was done, then the acid particles will have a bigger area to collide with, so more collisions will occur.
I am going to use the first factor for my experiment. I chose this because several different concentrations can be made up before the experiment.
I predict that as the concentration of the hydrochloric acid increases, the time taken for the magnesium to disappear decreases. I predict that when the concentration of the hydrochloric acid doubles, the rate of the reaction doubles. Therefore showing a pattern.
The collision theory describes how the rate of reaction increase (the time taken for the magnesium ribbon to disappear when it is reacted with hydrochloric acid) when the concentration of HCL increases. The theory states that the more concentrated the reactants, the greater the number of collisions between particles. This also explains why the greatest rate of reaction is usually as soon as the reactants have been mixed, i.e. they are both at their highest concentrations. As the reaction continues, the concentration of the reacting substances decrease and so does the rate of reaction.