But and Tube Measuring Scales
Safety: - As acid and Bunsen’s may be being used safety goggles should be worn at all times and all hair tied back. As glass is being used all bags should not be in the corridor and all should be careful when handling glass in case of breakage. All science classroom safety rules should be followed to ensure a safe environment.
Prediction: - In our experiment we shall be changing the concentration of the solution, making the solution weaker and stronger. I predict that when the solution has been weakened by water to make it less concentrated the rate of reaction will be slower and weaker. This will happen as there are less particles of hydrochloric acid reacting with the calcium carbonate, the fewer amounts of particles the less amount collisions with the calcium carbonate. Therefore when the hydrochloric acid is strengthened by doubling the amount of hydrochloric acid and adding it with the same amount of calcium carbonate the reaction will be stronger and quicker. This will occur as there are more particles in the solution reacting with the calcium carbonate, as there are more particles in the solution the number in collisions will greatly quickening the reaction time.
Method: - After all equipment has been collected and set up (e.g. clamp stand), and all safety rules are followed. First weigh the amount of calcium carbonate you will use i.e. 4g. Then decide if you will change the surface area, doing this will quicken or slow down the experiment. To change the surface area put your calcium carbonate in a pestle and mortar and grind down the chips into a powder, small chips or leave it in the size given. After you have decide and carried out this put the calcium carbonate into the chronicle flask. Then decide if you will change the concentration of the hydrochloric acid, to weaken the solution add water to strengthen the solution add more hydrochloric acid. When the chosen concentration has been made add this to the calcium carbonate. As soon as the hydrochloric acid has been added to the calcium carbonate put the but on which is connected to the Gas Syringe and begin timing. Time how long the gas syringe takes to reach a certain point or points e.g. take a reading at 5ml then 10ml then 15ml…etc. Then do another experiment changing the variables. It is advised to do each experiment more the n once to take an average, but all depends on the amount of time given.
Results: - in this experiment the surface area was changed and the calcium carbonate was grinded up into small chips. Doing this makes the surface area bigger so the hydrochloric acid particles have more to react with making the rate of reaction quicker.
There are no readings from 25 seconds onwards as the rate of reaction was so fast that no readings could have been taken as the Gas syringe was not big enough and had run out.
Analysis: - My predictions corresponded with the results and I have proved that changing the variables in experiments does change the out come of the reaction. We have proved that when the solution’s concentration is changed to a higher concentration the rate of reaction quickens, this occurs as there are more particles in the solution which collide more with the calcium carbonate reacting quicker. Weakening the solution means there were less particles in the solution meaning less collisions with the calcium carbonate slowing the reaction time down. The experiment was not entirely fair as when the acid was pored into the chronicle flask to react with the calcium carbonate there was a slight pause before the gas syringe was connected. Meaning some of the gas given off could escape into the atmosphere; this could be overcome by taking the experiment in an air tight container such as a vacuum so no gases could escape. Doing this will make the readings very accurate proving more that changing certain variables will change the outcome of the rate of the reaction. The experiment also could have been more accurate by taking more readings and then making an average. Also more variables could have been changed to promote different outcomes such as changing the surface area for each reading, instead of using small chips each time we could have used powder, small chips and the large chips for each experiment. Doing this giving more proof that different variables change the outcome of the rate of reaction.
