3. Analysis and Conclusions
Accuracy Of Results
Extending the Investigation
I am doing this experiment to find out how I can speed up the reaction rate between calcium carbonate and hydrochloric acid.
This is the equipment I will use:
The factors that could slow down or speed up this reaction are:
The size of the Calcium Carbonate (marble) pieces This will affect how fast the acid reacts with the marble, the smaller the pieces, the bigger the surface area so the reaction can take place faster. The amount of Calcium Carbonate The more calcium carbonate there is, the more carbon dioxide will be produced and the larger the reaction will be. The amount of Hydrochloric Acid The more hydrochloric acid there is, the more carbon dioxide will be produced and the larger the reaction will be. The temperature of the materials The temperature of the materials determines how fast the reaction will take place. The hotter the materials, the faster the reaction and vice-versa. The concentration of Hydrochloric Acid The higher the concentration (strength) of the acid, the faster it will react. The purity of the Calcium Carbonate pieces The purity of the calcium carbonate will affect the speed of the reaction also.
From previous experiments I have learned that if large pieces are broken into smaller pieces they react faster because they have more surface area. This is because at the molecular level, there are more molecules at the surface of the chips for the molecules of acid to react with when the chips are broken into smaller pieces. The same principle can be applied to the marble chips. The smaller the chips the more surface area so I predict that the smaller marble chips will react faster than the larger chips.
Here is the set up:
In this experiment I will be keeping the variables I mentioned earlier the same except one to keep the experiment fair. I will be changing the size of the marble chips to see which size reacts the fastest. The gas syringe is firstly clamped to the stand and a plastic tube and bung are attached to the syringe. The marble chips are then measured out (I will be using 2g of marble chips each time) and the hydrochloric acid (10ml) is added to the flask. The chips are then added and the bung is quickly placed over the flask to create an airtight seal. The amount of carbon dioxide in the gas syringe is read off every 10 seconds until the reaction stops or the gas syringe runs out of capacity (100ml).
Goggles must be worn at all times to prevent acid going in eyes. Gas syringes must be handled with care to prevent accidents
Dependant VariableValueHow Measured
Amount of carbon dioxide collectedAmount read every 10 seconds. 2 repeats for each size of marble chipGas syringe and digital stopwatch Independant Variable
Size of marble chipsPowder, small, medium and large chips prepared by teacher. 2g used each time.Size measured by third party. Weighed using digital scales. Control Variables
Amount of acid10ml each timeMeasuring Cylinder
Concentration of acid1 molar acidMeasured by third party.
TemperatureRoom temp. Approx 27CN/A
Purity of calcium carbonateAssumed the same puritySame batch used each time
Time(sec)Powder (ml of CO )Small
(ml of CO )Medium
(ml of CO )Large
(ml of CO )...