How the Concentration of Hydrochloric acid Affects the Rate of Co2 produced by Marble chips

. Drop 2.5g of small marble chips into the conical flask with 50ml of a varied concentration of hydrochloric acid.

2. Place the bung over the mouth of the flask and start the stop clock at the same time.

3. Record the Carbon dioxide collected after 30 seconds.

4. Then clean the equipment to make sure it cannot make the test unreliable.

5. Preset the equipment for a different concentration of acid.

6. Once all the results have been taken for the different concentrations I will plot a results table with an average coulomb, and graph to show the relationship of the gas produced against the concentration.

The five different concentrations I will be using for this experiment will be:

Cm3 of hydrochloric acid

(2mol/l)

Cm3 of water

50

0

40

0

30

20

20

20

0

40

Risk Assessments:

Before starting the experiment one should put on safety goggles and a lab coat to prevent the hydrochloric acid from damaging our eyes or clothes. As the acid is highly corrosive it should be handled with great care to avoid external or internal damage. If there is any split I will wipe it up straight away. To avert mistakes I will always label the beaker with the acid in it. The calcium carbonate (CaCo3) or marble in powder form is also dangerous and when it reacts with hydrochloric acid may spurt out and damage my eyes, this is the reason I wear eye protection. As an extra precaution I will not peer into a bare conical flask with the reaction taking place. I will also make sure I do not drop the apparatus.

Fair Test:

To keep a fair test I will make sure all the constant variables are kept the same. For instance I willl check the temperature as this could affect the speed of the reaction. I will also make sure that the concentration of acid is kept the same so the reaction doesn't speed up if there is slightly too much acid or slow down if there is slightly too much water for the certain concentration. I will try and keep all the chips roughly the same size and mass as this will also affect the speed of the experiment. I will be as fast as possible in starting and stopping the stop clock and making sure the chips are added at the same time. I will also keep account the number of extra bubbles in the eudiometer once the time has stopped.

Prediction:

I predict that the rate of reaction will increase as the concentration increases. This means that the amount of carbon dioxide is produced at a greater rate. See below for the graphs of 'gas collected against concentration' and 'rate of reaction against concentration':

Gas Rate of

Collected Reaction

Concentration Concentration

I believe that the gas collected will be proportionate to the concentration because as the concentration weakens, the gas collected decreases too as there is less acid to corrode the marble chips (which produce the Co2.) The other graph rate of reaction against the concentration) represents the same because a smaller concentration will mean a slower rate of reaction and vise versa. This is why the two are proportionate. Basically the two are stating that the higher the concentration the faster the rate of reaction because there is more acid to react with the calcium chloride so the more Co2 is produced as the calcium chloride gives this off.

Hugo Jones

Chemistry coursework