I aim to discover how different concentrations of Hydrochloric acid influence the rates of reaction. In order to carry out this investigation I have decided to use marble chips, which I will vary the sizes as powder, small chips and large chips. I will also be changing the concentration, the different concentrations are as follows 0.2m, 0.5m, 1m, 1.5, 2m. I have chosen these concentrations as they have a good range, we have to take this in to account, in view of the fact that if I was to use a concentration lower than 0.2m, the rate of reaction will be to slow or if I was to use over 2 molars, it is too dangerous to handle and violates the healthy and safety rules with in the lab. An advantage of using a good range of concentrations is that my results would also have a good range.
To proceed with my investigation I will have to wear safety goggles as I have to follow the lab regulations as well as keeping my eyes away from any harm.
To undergo with my investigation I have found out what a reaction is, how we measure the rates of reaction and 4 ways rates of reaction can be affected.
When two reactants collide together and form a new substance it is called a reaction. To measure the rate of reaction you observe either by how long it takes for the reactants to be used up or how quickly the products are forming. Varying the concentration, temperature, surface area and using catalyst all change the rate of reactions.
I am going to do preliminary experiment, ahead of the main experiment so I can make sure that I use the right methods and I can see if any of my aspects can be improved. Doing preliminary research helps me to do my final experiment as it makes it simpler to understand and go through as I will have done something similar beforehand
To keep it a fair test I used 0.5g of each substance and a concentration of 1 molar HCL.
The following tables show the results I got after the preliminary experiment.
This is a table to show the rates of reaction with 10cm³ of Hydrochloric acid
Size of substanceTime taken for reaction in secondsTemperature beforeTemperature afterObservation Mg15s24º34ºTemperature went up. Very quick reaction. Fizzing occurred. CaCo3
(big)More than 5 minutes24ºUnknownNever had enough time, took too long to react CaCo3
(small)24s24º24ºFizzing occurred, acid got used up, need more than 10cm³ of HCL CaCo3
(powder)15s24º25ºReaction took place very fast, fizzing occurred.
This is a table to show the rates of reaction with 2cm³ of Hydrochloric acid
Size of substanceTime taken for reaction in secondsTemperature beforeTemperature afterObservation Mg13s26º34ºTemperature went up. Very quick reaction. Fizzing occurred. Mg left over, need more acid CaCo3
(big)More than 5 minutes24ºUnknownNever had enough time, took too long to react, had some fizz CaCo3
(small)1min40s26º25ºFizzing occurred, acid got used up, need more than 10cm³ of HCL as there was still some marble left after reaction CaCo3
(powder)10s26º26ºReaction took place very fast, fizzing occurred. Powder was left over, as acid was used up
From my preliminary research I have found that small marble chips are the best substance to use, because in my preliminary research I used Mg and CaCo3 and from this I found that Mg has an exothermic reaction. An exothermic reaction makes it hard for me to keep the temperature the same in the final experiment, but with CaCo3, the reaction keeps the temperature more or less the same.
I also found that the Magnesium reaction is faster compared small Marble chips, so that is why I will use CaCo3.
For my preliminary experiment I used a concentration of 1 molar of 2cm³ and 10cm³ of Hydrochloric acid for every size of marble chips. For every reaction I timed rate of reaction and recorded the results on my...