Effect of Temperature on the Rate of Reaction Between Hydrochloric Acid and Calcium Carbonate

Introduction:
Temperature - Is a measure of the motion of particles, increasing the temperature will cause the particles to move faster because the reactant particles have more thermal energy from the heat. When particles move faster, more frequent collisions will occur and the collisions are more violent. This should increase the reaction rate. This will result in the particles colliding more frequently and increasing the speed of the reaction. Also when they have more energy there will be more chance of the collisions being successful because the activation energy will be attainable.
Hypothesis:
In a reaction between calcium carbonate and hydrochloric acid, the products calcium chloride, carbon dioxide and water are formed. I predict that the higher temperature of HCl acid, the higher the reaction rate will be, this is because at a higher temperature there will more fast-moving hydrochloric acid molecules per set volume. This means that there will be a higher chance of the calcium carbonate molecules colliding with the hydrochloric acid and reacting, with enough energy to break the activation barrier. This should in theory increase the rate of reaction as the temperature is increased.
The increase in the concentration should be directly proportional to the increase of the reaction rate at a given time.

Materials:
• 250g of CaCO3 marble chips
• 1 Thermometer
• 400mL 6M HCl
• 1 10cm3 graduated cylinder (±0.01cm)
• 1 Electronic balance
• 1 Dropper
• 6 50cm3 beaker
• 1 Boiling tube

Controlled Variables:
• Every experiment will be carry out at room temperature so that CaCo3 particles do have thermal energy at room temperature.
• The total surface area of the chips of calcium carbonate I will use in the reaction. However this will vary slightly as not all the chips are exactly the same size.
• I will keep the mass of the amount of chips I put in the hydrogen chloride solution the same.
• I will use the same volume of solution for each experiment.
• Concentration of HCl

Dependent variable:
The dependent variable I will be measuring is the amount of CO2 gas produced by the reaction in cm3. The more gas that is produced in the reaction, with a specific time, the faster the reaction is occurring.

Method/Procedure:

1. Set up the retort stand and clamp on your worktop.

2. Place the gas syringe in the clamp and attach the connector to its nozzle, making sure the plunger of the gas syringe is all the way in.

3. Starting heating HCl to a specific temperature (increasing each time and monitor it with thermometer)

4. Fill one boiling tube with 50c m3 of the heated solution you will be testing.

5. Place it in the test tube rack/holder.

6. When you are ready with the stop clock, put 10 of the calcium carbonate chips into the solution, quickly connect the syringe to the boiling tube and press start on the stopwatch. (This step must be done quickly yet carefully!)

7. After every 10 seconds from 0, read where the plunger is in the gas syringe and record the result in a table.

8. At 60 seconds take the last reading and stop the clock and disconnect the boiling tube and the syringe.

9. Pour the contents of the boiling tube into a sieve, leaving all the marble chips behind.

10. Wash the chips and the boiling tube in water. (if the boiling tube is washed, it can be used again for the experiment)