During this experiment I will be investigating if heating limestone and changing the concentration of the acid will affect the rate of reaction.
Before doing our main experiment, we will have to conduct another experiment, to see what concentration of acid we will have to use. We done this using 0.1M, 0.5M and 1M of Hydrochloric acid, and 0.1g of powdered limestone, we used powdered limestone, as it would be a fairer test, I think this as all the particles of limestone will be roughly the same size, the particles have a larger surface area than cubed limestone, therefore it will react the quickest. If you were to use cubed limestone it wouldn’t be fair as no cube will be exactly the same size. In conclusion to this experiment, 0.5M of acid was the best to use as it had the best measurable reaction time.
The equipment we will be using during this experiment is:
*Goggles (to protect the eyes from reactions)
*Measuring cylinder (to measure out the acid)
*Bunsen burner (to heat the acid to the right temperature)
*Test tubes (to hold first experiment in)
*Hydrochloric acid (the acid being used)
*Powdered limestone (the substance being used)
*Triangular stand (to hold the Bunsen burner)
*Timer (to time the reaction)
*Thermometer (to record the temperature)
The possible variables are:
*Temperature of acid- this will determine how quickly the reaction happens e.g. the limestone reacts faster or slower under a certain temperature. When the acid is heated, the particles gain
*Amount of Hydrochloric acid used
*Amount of limestone used
*Surface area of limestone- this will determine how quickly the reaction will happen e.g. If the limestone is cubed or powdered
*Concentration of acid- this will determine whether the limestone dissolves faster or slower.
The variable we have decided to change is the temperature as the question we are investigating is whether changing the temperature of the acid will affect the rate of reaction.
During the experiment we will be keeping the amount of hydrochloric acid and limestone used the same because if we use different amounts for each temperature it won’t be a fair test, and we won’t get the correct results we are wanting.
We will also keep our apparatus the same e.g. the glass beakers, this is because if we have for example a 10cm wide beaker and a 15cm beaker and we use the same amount of acid and limestone, the results will be different as both mixtures have a either larger or smaller space to react in.
During the experiment we will be recording the temperature at the beginning and end of each recording, the time taken for each recording, this will be repeated 3 times (the time taken), and the averages will be calculated for both the time taken and the temperature at the end of each reading.
*Firstly I will set up my equipment, shown in my diagram on the previous page; I will then tie my hair back and put on the safety goggles to prevent myself from danger. I will then draw a table to record my results on.
*I will check to see if anything is around that is able to set alight before lighting the Bunsen burner. When it is alight I will place the glass beaker on top of the wire rack containing the acid and thermometer
*When the acid has heated to 20 degrees I will remove the beaker and put the powdered limestone in immediately, as soon as the limestone is in the beaker I will start the timer, when the reaction has finished I will stop the timer and write down the result onto the table. I will then take the temperature of the acid; this will be the reading of ‘the temperature at end’. I will repeat this, another two times to make sure it’s a fair test.
*After the first temperature has been completed I will then do the 30 degrees reading, using the same method as above
* After the second temperature has been completed I will then do the 40 degrees reading, using the same method as above
* After the third temperature has been completed I will then do the 50 degrees reading, using the same method as above
*Lastly I will do the 60 degrees reading, using the same method as above.
Its important to repeat the experiment a number of times to make sure it’s a fair test, the more times you repeat it, the fairer the test is going to be. Another way for the test to be fair is to keep all the variables you will not be changing, the same. For example; to keep the amount of acid and limestone used the same.
In this experiment, the theory involved is the collision theory .It is the theory that when the particles get heated, they gain energy, bounce off of each other more often, causing a faster reaction.
In this investigation I will be investigating If heating the acid affects the rate of reaction.
Temp at start (c) temp at end (c) Average temp (c) Reaction time (s) time 2 (s) time 3(s) Average time (s)