Fair Test
To create a fair test all metals will be measured by accurate scales. The metals will be cleaned with sand paper to create a fair test. The volume of HCL will be measured in a lab-measuring cylinder to make sure that the amount of acid is accurate. Apparatus will be cleaned out before use to that nothing gets contaminated. Contamination will cause the results to be inaccurate. Also to create a fair test when using the metals I only used them in powder form so that everything is the same. I repeated the experiment three times so that I could retrieve accurate results and a fair test.
Background
I have created some equations explaining the reaction between the metal and the hydrochloric acid:
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Calcium + hydrochloric acid calcium chloride + hydrogen + (heat)
Ca(s) + 2HCL(aq) CaCL2(aq) + H2(g) + (Energy)
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Magnesium + hydrochloric acid magnesium chloride + hydrogen + (heat)
Mg(s) + 2HCL(aq) MgCL2(aq) + H2(g) + (Energy)
- Zinc + hydrochloric acid zinc chloride + hydrogen + (heat)
Zn(s) + 2HCL(aq) ZnCL2(aq) + H2(g) + (Energy)
- Iron + hydrochloric acid iron chloride + hydrogen + (heat)
Fe(s) + 2HCL(aq) ZnCL2(aq) + H2(g) + (Energy)
The metals react with the HCL and produce calcium chloride and hydrogen. Heat energy is given off.
Amount of acid and metals
This is a table of the metals with their relative atomic masses (R.A.M):
This is a table working out the mass of metals used:
Skill Area O: Obtaining Evidence
Results
I have presented the results in separate tables so that it is easier to read (all temperatures started at 26oC):
Experiment 1
Calcium
Magnesium
Zinc
Iron
Experiment 2
Calcium
Magnesium
Zinc
Iron
Experiment 3
Calcium
Magnesium
Zinc
Iron
Average Results
Calcium
Magnesium
Zinc
Iron
Sum Up
I have created a sum-up of the above results:
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Calcium reached 97oC in 0:30 minutes and declined to 90oC. It did this in 2:30 minutes.
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Magnesium reached 75oC in 0:30 minutes and declined to 66oC in 2:00 minutes.
- Zinc reached 29oC in 3:30 minutes and didn’t decline.
- Iron reached 27oC in 5:00 minutes and didn’t decline.
- As the metals went down in the reactivity series, the less vigorous the reaction.
Skill Area A: Analysing Evidence and Drawing Conclusions
Conclusions
I have created conclusions for each metal:
Calcium
From looking at my results tables and graphs you can clearly see that calcium reaches the highest temperature (97oC). This means that calcium is the most reactive metal out of the four metals available. Also just by looking at the reaction you can tell that it is the most reactive. The reaction was the most vigorous. The liquid turns dark black and bubbles viciously. The temperature increased very quickly (from 26oC to 97oC in 30 seconds). Thick steam rises showing that the reaction is very hot. Calcium reaches the highest temperature because it is higher up in the reactivity series, thus it will reach a higher temperature in the reaction than any other metal.
- Calcium + hydrochloric acid calcium chloride + hydrogen + (heat)
Ca(s) + 2HCL(aq) CaCL2(aq) + H2(g) + (Energy)
Magnesium
Magnesium reached the second highest temperature out of the four metals available (75oC). The reaction was not as vigorous as Calcium but it was vigorous. The temperature increased quite quickly (from 26oC to 75oC in 30 seconds). The reactions between Calcium and HCL and Magnesium and HCL are very similar. The only difference is that the reaction between calcium and HCL is a bit more vigorous and violent than the reaction between magnesium and HCL. The reactions are very similar because Magnesium is right behind Calcium in the reactivity series so the reactions are bound to be similar.
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Magnesium + hydrochloric acid magnesium chloride + hydrogen + (heat)
Mg(s) + 2HCL(aq) MgCL2(aq) + H2(g) + (Energy)
Zinc
Zinc reached the third highest temperature (29oC). The reaction was not very vigorous at all. The liquid didn’t turn black, but light grey. Steam did rise but it was very thin steam and there wasn’t a lot of it. The temperature increased very slowly (from 26oC to 29oC in 3:30 minutes). This reaction was slow because zinc is quite low in the reactivity series compared to Calcium and Magnesium.
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Zinc + hydrochloric acid zinc chloride + hydrogen + (heat)
Zn(s) + 2HCL(aq) ZnCL2(aq) + H2(g) + (Energy)
Iron
Iron reacted the slowest. It reached the lowest temperature (27oC). The reaction didn’t really have a visible reaction. All you could see was small bubbles coming off the iron and floating to the surface. This reaction took 5 minutes to increase in 1oC (26oC to 27oC in 5:00 minutes). No steam was present and the liquid didn’t change colour. This reaction was very slow and un-vigorous because Iron is so far down in the reactivity series.
- Iron + hydrochloric acid iron chloride + hydrogen + (heat)
Fe(s) + 2HCL(aq) ZnCL2(aq) + H2(g) + (Energy)
Prediction
I predict that calcium will give a more vigorous reaction and give off more heat. This is because calcium is higher up in the reactivity series than any other metal used in this experiment. Then I would imagine that magnesium would create the next largest reaction and give off heat. Following that will be zinc and then iron. I am predicting this information on the basis of the metals rank in the reactivity series.
Was my prediction correct?
Yes, my prediction was correct because of my knowledge of the reactivity series. I knew that if the metal was higher up in the reactivity series, it would give off a larger and more vigorous reaction that the metal lower down in the reactivity series.
Skill Area E: Evaluating Evidence
Was my method correct, could it be used again safely?
My method did give accurate results but you have to be careful with the experiment. The equipment should be cleaned to prevent infections. If the acid gets infected the results will probably be incorrect. I could have probably carried out the experiments in a glass beaker instead of a polystyrene cup because sometimes the polystyrene cups were not very clean and could cause and infection.
Do I have enough results to create a good conclusion?
I think I do have enough results. Repeating the experiment is the best way of getting good results and a good average result. It gives you more reliable results and thus giving you a better conclusion.
How could I improve my experiment?
I think the only way I could improve my experiment is to have used a glass beaker instead of a polystyrene cup. I could have recorded the results at smaller time intervals but I think 30 seconds is a good time to read the thermometer and write down the results with enough time to prepare for the next reading.
What other experiments could I have done?
This is a list of the other experiments I could have used to place Calcium, Magnesium, Zinc and Iron In the reactivity series:
- Reacting the metals with water
- Reacting the metals with oxygen
- Reacting the metals with steam
