In the investigation I am going to find out how the surface area affects the rate of reaction by measuring the amount of gas produced and weight loss in a reaction between small/large pieces of Marble Chips (Calcium Carbonate) and Hydrochloric acid per minute.

Hypothesis.

The rate of reaction increases when the surface area of a solid reactant is increased. This happens because by increasing the surface area we are also increasing the rate of collisions between the particles. When there is more of the reactant to react with the reaction speeds up. Therefore, my hypothesis is: the reaction will be faster when using small chips, so the gas will be produced faster (the same amount of gas will be produced in all experiments).

Apparatus.

* Conical flask

* Cotton wool

* Scales

* Measuring cylinder (50ml)

* Stopwatch

Method.

1. Take one large piece of Calcium Carbonate and record its weight.

2. Measure 50cm of hydrochloric acid (using measuring cylinder).

3. Place the flask on scales.

4. Add the marble chip and hydrochloric acid to the conical flask at the same time and close the top with cotton wool to prevent the spitting out of the reactants.

5. Start off the stopwatch (you might want to ask someone else to do this for you in order for the timing to start as soon as the reactants are mixed).

6. Record the weight loss (gas given off) every 20 seconds for the 10 minutes of the reaction. Repeat the experiment using large marble chip.

7. Repeat the whole experiment again using other sizes of the marble chips. Make sure you take the same amount of chips and

hydrochloric acid at each time.

8. If time allows, repeat the experiments in order to improve the reliability of the results.

In order to make the experiment safe goggles and lab coats must be worn at all times as a protection in case of a spillage.

The independent variable in my investigation will be the surface area of the Marble Chips, however their mass will need to be controlled as well as the amount of hydrochloric acid and its concentration (2moles) used in all experiments in order to make it a fair test. The amount of gas produced will be measured (by using scales) as a dependent variable. The temperature will be kept constant as the room

temperature.

Analysing the results.

From the obtained results I was able to work out the rate of reaction in all 3 test (12 experiments), they are as followed:

Test 1:

* Marble Chip powder took 2 minutes to produce 0.45g of gas in total; therefore the rate of reaction was 0.45 ¸ 2 = 0.23g per minute (to 2 decimal places)

* 2-6mm Marble Chips took 9 minutes 20 seconds to produce 0.48g of gas in total; therefore the rate of reaction was 0.48 ¸ 9.3 = 0.05g per minute (to 2 decimal places)

* 6-9mm Marble Chips took 10 minutes to produce 0.46g of gas in total; therefore the rate of reaction was 0.46 ¸ 10 = 0.05g per minute (to 2 decimal place)

* 9-12mm Marble Chips took 9 minutes 40 seconds to produce 0.45g of gas in total; therefore the rate of reaction was 0.45 ¸ 9.7 = 0.05g per minute (to 2 decimal places)

Test 2:

* Marble Chip powder took 1 minute 40 seconds to produce 0.47g of gas in total; therefore the rate of reaction was 0.47 ¸ 1.7 = 0.27g per minute (to 2 decimal places)

* 2-6mm Marble Chips took 8 minutes 40 seconds to produce 0.46g of gas in total; therefore the rate of reaction was 0.46 ¸ 8.7 = 0.05g per minute (to 2 decimal places)

* 6-9mm Marble Chips took 9 minutes 40 seconds to produce 0.46g of gas in total; therefore the rate of reaction was 0.46 ¸ 9.7 = 0.05g per minute (to 2 decimal place)

* 9-12mm Marble Chips took 10 minutes to produce 0.45g of gas in total; therefore the rate of reaction was 0.45 ¸ 10 = 0.05g per minute (to 2 decimal places)

Test 3:

* Marble Chip powder took 3 minute 40 seconds to produce 0.42g of gas in...