I am investigating how the rate of reaction differs when we change the concentration of Hydrochloric Acid whilst reacting with Magnesium. The rate of reaction is explained by the Collision Theory.
This theory explains how various factors affect the reaction rates and how chemical reactions occur. The 4 factors of the Collision Theory are:
• Temperature
• Concentration
• Surface area
• Catalyst
I am investigating how different concentrations of acids affect the rate of reaction. However I must control the temperature, surface area and catalyst by keeping them the same throughout the experiment.
I used 5 different concentrations of acid. These were, 2.0(mol), 1.6(mol), 1.2(mol), 0.8(mol) and 0.4(mol). The reason I used such a variety of acids was to make sure my results were more reliable and to ensure I got wider range of results.
I kept the temperature at room temperature and the surface area of the solution always added up to 40cm3. The magnesium was cut to 4cm each time I did the test. I kept these three factors the same to make it a fair test and to ensure my results were more reliable. I didn’t use a catalyst as it speeds up a reaction and my reaction was fast enough without using it.
I used a wide variety of different concentrations so I was able to see what effect it had on the rate of reaction. It also showed a positive correlation on my graph which helped me interpret my results.
I did a preliminary test (practice test) to see how we would construct each experiment and who would do what jobs, for example marking the gas produced or timing every two seconds of the reaction. It also helped me to find out how many seconds I should mark the amount of gas produced. I started off with 4 seconds but for the 2.0(mol) concentration the reaction was fast, so I marked every two seconds instead to get a more reliable result. Doing the preliminary test help make my final experiment more accurate and reliable.
To ensure my results were reliable I