The formula for this reaction is
Marble Chips + Hydrochloric Acid = Carbon Dioxide + Water + Calcium Chloride
CaCO3(S) + 2HCL(AQ) = CO2(G) + H2O(L) + CACL2(AQ)
Also I think that higher concentrations of acid will make reaction times faster because of the collision theory, this is the more particles in a substance the more they collide together and if there are fewer particles there will be less collisions.
Fair Test
All these factors could affect the test from being a fair test
- Variable
- Particle Size
- Factors remaining the same
- Same mass of limestone
- Same volume of acid
- Same molar acid
- Apparatus
- Large Beaker
- Weighing Scale
- Measuring Cylinder
Safety
- · Be careful handling the acid.
- · Wear goggles at all times.
- · Be careful dropping limestone into glass beakers.
Equipment:
- Stop Watch
- Plastic Clip
- Metal Stand
- Bowl
- Water
- Burette
- 1grm of small and large marble chips for each experiment
- Concentrations of 3M, 2.5M, 2M, 1.5M and 1M
- Measuring Cylinder
- Scales
- Delivery Tube
- Bung
- Conical Flask
Method
- Set up apparatus as shown in diagram.
- Weigh the correct mass of limestone.
- Add acid to the limestone and record the change in mass.
- Repeat for each chip size.
Results
NOTE: Results were recorded in groups
Using 1 gram of small marble chips
Using 1 gram of large marble chips
Conclusion.
The prediction I made was correct as the smaller the particle size the greater the mass loss. This is because of the collision theory - the higher the total surface area the more particles can collide and react. The larger chips have a smaller surface area and don't decrease as much in mass. Although the larger block may have the same mass as the four small ones put together, the larger chips have a smaller surface area. However there were problems with the experiment because some of the water could condense. Also there could be some human error, making inaccurate timing and starting the stopwatch mass making an unfair test.
Evaluation
My experiment went well. There doesn't seem to be any odd results on the graph. If I were to retake this experiment again I would consider a more accurate measuring device to measure out the substances exactly as well as calculating a better time reading a better time reading of each test. I would also consider experimenting with different masses of marble chips. A change in temp would also be a interesting development to see what happens and what effect it would have.