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Rates Of Reaction

HOW THE CONCENTRATION OF 2HCl AFFECTS THE RATE OF REACTION

Aim: In this investigation we are trying to find out whether the effect of changing either temperature or concentration on the rate of a chemical reaction using a gas collection method speeds up the rate of reaction.

Magnesium + Hydrochloric Acid             Magnesium Chloride + Hydrogen

Mg + 2HCl         MgCl2 + H2
Scientific Knowledge
Rate is something we come across all the time in our lives. Rate is how fast something is travelling; an ideal example is if a plane flies 2000 kilometres in 1 hour we say it flew at a rate of 2000 kilometres per hour. Time measures rate, we use units such as seconds, minutes or hours. The rate of reaction is what we will be measuring in the investigation; it tells us more than the speed of the reaction which is taking place. It notifies us exactly how fast the reaction is going and long it is going to take before completion. Rate of reaction is based on two factors; the amount of the reactant which is exactly used up per unit of time as well as the amount produced for per unit of time.

Concentration
The actual rate can be changed by altering the amount of concentration of the reactant. The investigation we are carrying out is an ideal example; when the magnesium reacts with hydrochloric acid and once I repeat the investigations a few times we can change the concentration of hydrochloric acid to see how the concentration actually affects the rate. This will allow us to see whether decreasing or increasing the concentration will actually bring a change in the speed of the reaction itself. Altering the concentration is only one of the methods in which can be used to change the rate.

Temperature
The temperature of the reactant can provide unreliable results. Before the
magnesium strip is placed into the solution of hydrochloric acid, the oxide layer needs to be removed; this is done by sanding down the magnesium strip so oxidation does not greatly affect...