Hydrochloric Acid And The Marble Chips example essay topic

dgfhhdhdInvestigating rates of reaction AIM The aim of my investigation is to find out how rates of reaction are affected by temperature, specifically how the rate of the reaction between hydrochloric acid and marble chips is affected by the temperature of the hydrochloric acid. VARIABLES The variables in this experiment are: . The mass of the marble chips. The size of the marble chips.

The amount of hydrochloric acid used. The concentration of hydrochloric acid used. The temperature of the hydrochloric acid. The speed at which CO 2 is produced. Equipment used My input variable is the temperature of the hydrochloric acid. I have chosen this because, according to the kinetic theory, the temperature should increase the speed and energy of the particles, therefore there are more collisions between particles, and the rate of reaction increases.

My output variable is the speed at which CO 2 is produced. I have chosen this because the reaction between the marble chips and the hydrochloric acid produces CO 2, therefore if there is a higher rate of reaction there should be more CO 2 produced in the same amount of time. All the other variables will be controlled in order to make the experiment a fair test and so that any changes in the rate of reaction can only be due to my input variable: . I will keep the mass of the marble chips constant by carefully measuring out and using the same mass of marble chips each time - this will be 5 gm; . I will ensure the size of the chips are constant by using very similar size chips and approximately the same number of chips each time; . I will keep the amount of hydrochloric acid the same for each experiment by measuring it out beforehand - this will be 50 ml; .

The concentration of the hydrochloric acid will be kept constant because I will use acid of the same concentration from the same source (... ); . I will use the same equipment each time, as shown in my method. All the above points should ensure that my investigation will be fair, and that my results should be reliable. METHOD Firstly, I will set up the equipment as shown above. Then I will measure out the hydrochloric acid with a measuring cylinder and pour it into the conical flask.

Next I will measure out the marble chips, ensuring the chips are of the same size, and using accurate electronic scales. I will then heat, if needed, the acid to the required temperature using the bunsen burner. I will then add the chips to the hydrochloric acid and immediately put the bung on the flask and start the stop clock. When 50 cm of gas has been collected in the syringe, I will stop the stop clock and record the result in a table. I will heat the acid to 8 different temperatures, from 20-90 C, at 10 C intervals, using the same method each time as described above. I will repeat my experiments 3 times and calculate an average to make my results more reliable and show up any anomalies that might occur.

PREDICTION 1. I predict that the hydrochloric acid and the marble chips will react to produce carbon dioxide gas, water and calcium dichloride. This is shown in the following equation: CaCO 3 (s) + 2 HCl (aq) 'U CaCl 2 (aq) + H 20 (l) + CO 2 (g) calcium carbonate + hydrochloric acid 'U calcium dichloride + water + carbon dioxide 2. I predict that as the temperature of the hydrochloric acid increases, the time taken for 50 cm of gas to be collected in the syringe will decrease.

This is because as the temperature increases, the particles in the hydrochloric acid and the marble chips move faster, so they collide more often and with more energy. If the particles collide with enough energy, the level known as activation energy, then the initial bonds will be broken. The line of best fit on the graph is curved because.