When the marble chips (Calcium Carbonate) are added there will be more collisions if the concentration is higher, so there will be more particles in the conical flask. Other key factors, which can affect rates of reactions, are the temperate of the Hydrochloric Acid, if the temperature of the Hydrochloric Acid is warm then the rate of collisions would be much faster. If there is a catalyst involved (Which speeds up the rate of a reaction, but are never used up) and also the size of the particles affect the rates of reaction, because if there are more particles with a bigger mass the reaction time would be different to the time taken if the particles are smaller.
Equipment:
Conical Flask
Syringe
Rubber tubing with rubber bung
Stopwatch
Goggles
Pipette
Measuring cylinder
Health and Safety:
For health and safety we had to make sure we wore goggles whenever we opened a bottle of Acid and also when whenever a reaction is taking place. If the Hydrochloric Acid were to fall on the table floor or anywhere else then you would have to wipe it up immediately with a paper towel, lids to bottles of acid should be closed straight away after you have poured the required amount into your beaker, test tube etc. Girl’s hair would have to be tied back and also it is essential that all bags and stools be tucked in so people do not trip over them. If people are wearing glasses it is also advised to wear goggles.
Method:
- Take out all the equipment mentioned above in equipment list.
- Measure 25ML of Hydrochloric Acid using a measuring cylinder and then pour it into a conical flask.
- Measure 2.5 grams of Calcium Carbonate then apply it to the Hydrochloric Acid, which is already in the conical flask. When the Calcium Carbonate is added start the stopwatch instantly.
- Stop the stopwatch and record the timings when the Calcium Carbonate has dissolved.
- Repeat this experiment with different concentrations of Hydrochloric Acid, with 1, 1.5, 2, 2.5 concentrations of Hydrochloric Acid.
Diagram:
This is a diagram of what my basic apparatus when set up looked like. The Hydrochloric Acid and the Calcium Carbonate when they where mixed with each other. This diagram does not show what happens, once everything has been mixed together.
Conical Flask
Hydrochloric
Acid
Calcium Carbonate
Observation:
When the Calcium Carbonate and the Hydrochloric Acid where together in the conical flask, it fizzed up for a certain amount of time. The amount of time taken depended on the concentration of the Hydrochloric Acid, the higher the concentration was the faster the reaction happened.
Results:
Graph:
This graph shows the results of the three experiments, I think the first experiment looks the most accurate.
Evaluation:
The investigation I carried out was accurate in terms of my results because they where all almost the same as each other, with only a few seconds difference between each. What I predicted was right as the higher the concentration is, the faster the rate of rate of reaction is. I also achieved my aim, which was to investigate the effects of different concentrations of Hydrochloric Acid when mixed with Calcium Carbonate.
Improvements:
If I did this experiment again I would have asked someone to start the stopwatch at the exact second, of me adding Calcium Carbonate to the Hydrochloric Acid. I would have also made sure I would have weighted how much Acid there was in each conical flask before starting the experiment. Apart from these improvements I could not improve anything on the practical side. But what I could have improved on, on the theory side is drawing the graphs on Microsoft Excel instead of hand drawing them, and also try and make the picture I drew for the hypothesis, on the computer.
