The Reactivity Series.
Aim:
To find the order of reactivity using 5 metals; Magnesium, Copper, Zinc, Iron and Calcium. I will find the order by adding each metal with Copper (ii) Sulphate, (Cu SO4), and finding there exothermic temperatures through out the experiment.
Prediction:
I think the order of reactivity for these five metals will be: Calcium, Magnesium, Zinc, Iron and Copper. This is because of where each metal is placed in the Periodic Table. Group 1 and 2 are more reactive than the transition metals, and the further you go down a group, the more reactive the metal gets. That is why Calcium is one period below Magnesium. Iron, Zinc and Copper are transition metals, meaning they come last. To find out the reactivity of the transition metals, you see how reactive each one is when it is added to an acid and water solution.
No experiment is needed to be carried out with Copper, as Copper (ii) can not displace it's self in the solution - Copper (ii) Sulphate. The results will probably stay the same as the room temperature or even the temperature of the Copper (ii) Sulphate. Though, to make these experiments a fair test, and to be certain that my hypothesis is correct, I shall do the Copper experiment.
I think the graphs will all start at room temperature and as soon as the
Cu So4 is added the temperature will rise. Of course Calcium will be the highest and copper will be the lowest on the graph, but still, I think they will all rise and then slowly drop back to room temperature after a while - some may take longer than others.
I will find out the order of reactivity, of these five metals, because of displacement. Displacement is when a more reactive metal pushes out a less reactive metal from its solution. I will know if this has happened by the temperature increase and maybe even if the reaction gives off hydrogen gas. Like this:
Magnesium + Copper (ii) Sulphate Magnesium Sulphate + Copper
Mg + Cu (ii) SO4 Mg SO4 + Cu
An exothermic reaction is when two or more substances are mixed together chemically. They then produce their own energy and heat making the temperature rise. In these set of experiments Copper (ii) shall not create any heat, as it can not displace its self.
In our school book (Chemistry for you National Curriculum edition for GCSE),is listed the reactivity series confirming my hypothesis. Here is the full order of the reactivity series:
K Potassium Zn Zinc
Na Sodium Fe Iron
Li Lithium Pb Lead
Ca Calcium Cu Copper
Mg Magnesium Ag Silver
Al Aluminium Ag Gold
Pt Platinum
Apparatus:
Plan:
. Firstly to make sure of safety always wear goggles at all times and never leave the thermometer on the side of the bench, as it may role off, or ...
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In our school book (Chemistry for you National Curriculum edition for GCSE),is listed the reactivity series confirming my hypothesis. Here is the full order of the reactivity series:
K Potassium Zn Zinc
Na Sodium Fe Iron
Li Lithium Pb Lead
Ca Calcium Cu Copper
Mg Magnesium Ag Silver
Al Aluminium Ag Gold
Pt Platinum
Apparatus:
Plan:
. Firstly to make sure of safety always wear goggles at all times and never leave the thermometer on the side of the bench, as it may role off, or clamp it down too hard that it breaks.
2. Measure out the metals (Ca, Mg, Zn, Fe, and Cu) on a level spatula.
3. Set up the apparatus as in the diagram above, using a polythene cup so no heat is lost. Make sure the thermometer is in the middle so the polythene cup.
4. Measure out 25cm3 of Cu SO4 in a narrow measuring cylinder, to make sure the volume is correct
5. As soon as the Cu SO4 is added to the cup containing the metal start the stop clock.
6. Every 20 seconds for a period of 3 minutes take the temperature, and watch the reaction.
7. At the end of each experiment do not through the solution down the sink, as all of them will be dangerous.
Safety:
Substance or The hazard. Precautions to Source of
Apparatus. Minimize it. Information.
Thermometer. Toxic mercury Support it with a General knowledge
and made of clamp stand.
Glass.
Magnesium. Explosive reaction Leave no water Hazard cards.
With water. on the bench.
Copper. Dangerous with Wash the cup Hazard cards.
Magnesium. Out well after
previous
experiments.
Iron. Irritant with Wear goggles. Hazard cards.
skin and eyes.
Zinc Water can ignite Wear goggles. Hazard cards.
spontaneously.
Calcium. Dangerous with Wear goggles Hazard cards
Water, as hydrogen and don't and teacher.
is formed. inhale fumes.
Procedure:
Carry out exactly the same experiment as in the plan on page 2.
Fair test:
. I repeated the test three times to get an over all average.
2. I used a narrow measuring cylinder to get the volume as close to 25 cm3 as possible.
3. It was very hard to get the same amount of metal each time as metals have their own unique mass. So I tried to get the flattest level spatula of metal possible each time.
4. After washing out the cup to repeat the experiments, you have to make sure all the water was gone, as this could have diluted the Cu SO4, altering the end results.
5. The room temperature was the same (luckily) each time, though this could have had a large affect on the end results as well.
6. When repeating an experiment, don't change any thing.
Results: For these sets of results I recorded the time in; 20 seconds, 40 seconds, 60 seconds, 80 seconds, 100 seconds, 120 seconds, 140 second, 160 seconds, 180 seconds. They are listed below.
Calcium;
Experiment 1.
Experiment 2.
Experiment 3.
Average.
60
51
60
57.3
62
57
61
60
58
56
59
57.6
51
51
57
53
47
49
35
50.3
46
47
32
41.3
45
44
30
39.6
47
52
49
48.6
45
42
48
37.6
Magnesium;
Experiment 1.
Experiment 2.
Experiment 3.
Average.
27
26
26
26.3
26
27
28
26.8
26
27
28
27
26
27
29
27.5
26
27
31
28.5
27
28
31
29
28
28
31
29
28
28
32
29.5
29
28
32
29
Zinc;
Experiment 1.
Experiment 2.
Experiment 3.
Average.
29
29
27
28.3
29
29
28
28.6
29.5
29
28
28.8
29.5
29
28
28.8
29.5
29.5
28
28.9
29
29
28
28.6
29
29
28.5
28.8
29
29
28
28.6
29
29
28
28.6
Copper;
Experiment 1.
Experiment 2.
Experiment 3.
Average.
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
23
Iron;
Experiment 1
Experiment 2
Experiment3
Average
23
22.5
23
22.8
23
22
23
22.6
23
22.5
23.5
23
23.5
22.5
23
23
24
22.5
23
23.2
24
22.5
23
23.2
24
22.5
23
23.2
24
22.5
23
23.2
24
22.5
23
23.2
Analysis:
From the graph I can see that my prediction was correct about the order of reactivity. Though there were a few things I didn't suspect.
Calcium's temperature was allot higher than I expected and cooled very quickly. As soon as the Copper (ii) Sulphate was added to the metal, a reaction was noticeable. This was a slightly violent reaction, where there was a large amount of bubbles, and a hydrogen gas was given off. After 1 minute the bubbling stopped and you could see two, (a light blue and dark blue) new solutions mixing together, this was the alkali solution.
There were three temperatures below the line of best fit. The first reading I think was normal, but the other two at 120 seconds and 140 seconds must have been a mistake. Then at 160 seconds the temperature roses by 8C, and was above the line of best fit. Maybe this was something to do with a larger calcium crystal having a late reaction because it could have been coated in something like oil, or too much calcium oxide. Luckily the temperature dropped and the line of best fit ran straight through the last point.
Magnesium was allot lower in temperature, than my first experiment-Calcium, which I thought strange as they are next to each other in the Reactivity Series. The reaction was also noticeable as soon as the Copper (ii) Sulphate was added, but not as much as with Calcium. The solution bubbled but no hydrogen gas was given off, as this will only happen if the Magnesium is mixed with an acid. The temperature rose very slowly, about 5C every 20 seconds. The only strange increases were at 100 seconds where the temperature rose 10C and at 140 where the temperature stayed the same. The difference between this experiment and the Calcium was that Calcium reached its highest temperature at the beginning and dropped through out the experiment. Magnesium on the other hand started low and the temperature rose gradually each time. Its highest temperature was at 160 seconds where it reached 29.5C.
Zinc's reaction I thought was very strange. It's first temperature started above Magnesium's temperature! These sets of results though, never left the region of 28C, though the temperature change differed the odd milli degree. When the Copper (ii) Sulphate was added to this metal you didn't see any reaction, only that the temperature rose slightly. The line of best fit only ran through two of the point's recorded-at 60 seconds and at 180 seconds, and its highest temperature was in the middle of the tests at 100 seconds.
Iron too was a very boring experiment, as it only reached 23.2C from 22.8C, and the temperature varied over a 4degree temperature span, which was less than Zinc. It seemed all the point's were on the line of best fit which meant the experiment was successful even though the temperature rose very little.
The Copper experiment was exactly what I predicted, even the temperature was correct. A metal can not displace its self. What I saw in the polythene cup was the blue Copper (ii) Sulphate, with the orange copper floating on the top. The temperature stayed on room temperature (23C) and so making the line of best fit run through all points.
Evaluation:
The experiment's results were good for the use I needed them for. Though to explain the large leap between the Magnesium and the Calcium experiment was because of how I measured out the metal to begin with. Each metal has its own weight and mass meaning the reactions will be different. Each metal was measured out as a spatula and not by its atomic mass, if I knew how to do this I would have done it to make my experiments more correct.
Also the accuracy of my results could have been a reason why some points were slightly off the line of best fit. I tried to make the reading correct and to an exact 20 second's between each reading, but of course it is not always possible to do this, this could also be a reason why some results were incorrect.
I think my results are good enough to draw a fair conclusion for the order of reactivity of the five metals, but if I wanted the precise results of the temperatures of all the metals in the Reactivity Series, I would improve how I carried out my experiment.
If it were possible, I would measure out each metal by its atomic mass, and I would do the experiment setup to a computer to get the most accurate results I could.
The Order of Reactivity!
By Kathryn Hinchcliffe.
