I have been given several different concentrations of Hydrochloric acid and asked to carry out an experiment to find out what factors affect the rate of an acid rain reaction.

Plan

I plan to find out which concentration of acid will produce the fastest reaction. I will do this by putting the concentration in order of fastest time first. I will do this by performing the experiment with each different concentration of acid. In one conical flask I will put Marble powder and add the acid then place a bung in the top with a tube coming out of it going into another conical flask containing Lime Water, the Carbon Dioxide released during the reaction will be bubbled through the lime water in a conical flask on top of a piece of paper with a cross drawn on it. The reaction will be timed until the cross is no longer visible due to the cloudiness of the limewater this will show the rate at which Carbon Dioxide is produced.

The pieces of equipment I will be using are; different concentrations of acid, two conical flasks, a bung, a tube, lime water, marble powder, scales, two beakers, measuring cylinder, and weighing boat for scales, a spatula, and a stop watch.

Diagram

                                               

Variables

        

        Input

The variable I will be changing is the concentration of the acid. These concentrations will be; 2M, 1.5M, 1M, 0.5M and 0.1M.

        Output

                I am measuring the time taken for the limewater to go cloudy enough for the cross on the paper to become not visible. I will measure the time taken for the limewater to go cloudy enough for the cross on the paper to become not visible by using a stopwatch. I plan to do this 3 times for each crisp.

        

Controlled

                I will keep the Volume of the acid at 100ml as well as the limewater. I will use a measuring cylinder to measure the volume of acid and limewater. Using a different amount each time would cause the rate of reaction to change, as volume is another factor of rate of reaction. I shall use the same mass of marble powder each time (15g) using a weighing boat and scales as again different masses can affect rates of reaction

Method

1. Set up equipment as shown in diagram.
2. Add marble powder to acid and quickly apply bung and start stopwatch.
3. Watch cross under conical flask of limewater und it is no longer visible and stop stopwatch.
4. Record time on table. Repeat 3 times.
5. Repeat all but instructions 1) for other concentrations.

Safety

        To be safe I will wear goggles at all times, keep stools under benches, clean up any spillages and wash my hands after the lesson has ended.

 Table Of Results

       =  Anomalous Results (not included in averages)

Graphs

        See graph paper

        

Analysis

        The rate of reaction increases as the input variable quantity is increased. This is shown by my graph, it is a curve showing increase in concentration leads to lower rate of reaction (time). These patterns occur due to the collision theory that the more acid particle the more likely the will be contact between acid and marble powder grains though I do not believe my experiment to be very accurate or reliable (see evaluation) my original prediction was correct.

Evaluation

        The odd results can be account for by the unreliability of my experiment/method. Each time we performed the experiment we had no way of being able to put the bung in the conical flask at exactly the same time so carbon dioxide escaped and in different amounts for each experiment. Most of my repetitions were all similar except for the anomalous results shown in the table above.