Aim: We will measure the loss in mass of the marble chips (CaCO 3 ) as it reacts with Hydrochloric acid (HCl). This one method of measuring the rate of reaction. We will use a balance to measure this mass loss as the reactants are used up to form product.
* As Hydrochloric acid is corrosive wear a lab coat, gloves and safety goggles. * Take care when using the glassware not to cut yourself. * When the reaction is taking place Carbon dioxide gas is given off and it bubbles. Place a cotton wool stopper in the top of the conical flask to prevent any to the HCl splashing out but the cotton wool allows the gas to escape.
1. Weigh 2 g of marble chips on weight boat
2. Put conical flask on balance and zero
3. Add 2g of Marble chips to conical flask.
4. Add 25 ml of 1 M HCl.
5. Stopper with cotton wool.
6. Start stop watch immediately and record the mass every 30 Seconds for around 5 minutes. 7. Pour away the solution and rinse the marble chips in the flask with distilled water
As the reaction was taking place, there was vigorous bubbling seen in the conical flask. This bubbling was due to the release of the carbon dioxide gas (See chemical equation below).
As can be seen from the graph, there is a drop in mass of the reactants (HCl and CaCO3 ) over time. There are some possible areas of error while carrying out this experiment.
1. We need to record the initial mass of the reactants i.e. Marble chips and Hydrochloric acid. This value was a little difficult to measure accurately as the reactions starts to take place as soon as we add the HCl. We decided to take our time zero to be the point at which we added all the HCl into the conical flask. (See point 4)
2. We also noticed that the marble chips were stationary. Although not available, a magnetic stirrer would be a...