Lab: Some Metals Are More Reactive Than Others

Aim: To compare and rate the reactivity of different metals in HCl (hydrochloric acid).

Title and date: Lab: Some Metals Are More Reactive Than Others was gone through on the 7.12.09 (d/m/y)


Type
What?
How?
Independent
The type of metal
We shall use Cu (Copper), Zn (Zink), Al (Aluminum), Mg (Magnesium), Fe (Iron)
Dependent (what we measure)
The reactivity rate of the metal (in this situation, amount of bubbles)
5 metals will be each put into a different test tube, observe which one bubbles the most during the first minute
Controls/Constants (keep same)

- Time of testing
- Person measuring/carrying out experiment
- Amount of metal
- Amount of acid
- Test tube size


- Use stop watch
- Use same person
- Use 1 gram of each metal
- Use 20 ml of acid for each test tube
- Use the same type of test tube



Hypothesis:
If we test the reactivity of the metals by looking at the amount of bubbles, then the most reactive metal would be Magnesium; the second most reactive metal would be Aluminum; the third most reactive metal would be Zinc; the fourth most reactive metal would be Iron and the least reactive metal out of the five would be copper because Magnesium is closest to the left of the periodic table therefore it is more metallic than others while copper is closest to the right meaning that it is the least metallic out of the five.


Equipment and Materials:
- 50 ml of HCl (Hydrochloric acid)
- 1 gram of powder form of each metal
- 5 test tubes
- Stop watch
-Rack

Method:
1. Gather materials
2. Pour 20 ml of hydrochloric acid into each test tube
3. Put each metal into a different test tube at the same time
4. Start stopwatch when metals touch the surface of HCl
5. Record observations throughout one minute

Diagram of Apparatus:

Diagram_Of_Apparatus.JPG

Observations:
Observations for How the 5 Metals React

Metal
Observations
Zinc
- Bubbles appear rapidly
- here are lots of bubbles
- Transparent
- Pieces of zinc go up and down

Copper
- Can hardly see anything happen
- Sometimes can see some bubbles
- Sank at the bottom

Magnesium
- Lots of bubbles came immediately after magnesium was inserted
- Solution became white
- When test tube was touched, felt pretty hot
- Steam is seen after about 10 seconds
- Magnesium stays at the bottom

Aluminum
- Didn’t mix
- Aluminum is insoluble
- No bubbles seen

oh_awesome!.jpg
Conclusion:
After doing this experiment, we found out that each element has a different rate of reactivity in hydrochloric acid (HCl). The most reactive element was Magnesium; the second most reactive element was Zinc; the third most reactive element was Iron; the fourth most reactive element was Copper; the least reactive element was Aluminum.
Element (Metal)
Ranking of reactivity (1-5)
Zinc
2
Copper
4
Magnesium
1
Aluminum
5
Iron
3


After doing the experiment and looking at our results, we found out that our results say that our hypothesis is wrong though it is still right in a way. Our results show that Aluminum is now the least reactive metal while our hypothesis stated that it was the second most reactive metal out of those five. Therefore, the ranking position of the elements before Aluminum has now increased by one.
The ranking of reactivity can be explained by looking at the periodic table. Magnesium is the most reactive metal because it is closest to the bottom left of the periodic table (which is the area of the most reactive metals).
"You could argue that the activation energy will fall as you go down the Group and that will make the reaction go faster." (Kim Clark http://www.thenakedscientists.com/forum/index.php?topic=26145.0)

Evaluation:
Observations alone were not reliable enough for this experiment because numbers to measure quantitative observations were not present in our experiment. The experiment could have gone wrong in the process, such as measuring the materials, hydrochloric acid and the five powdered metals we have used. The method used the bubbles as the dependant variable. Although this was a good way to measure if there was a reaction or not, I though it wasn’t as accurate when measuring the level of reactivity.

Weakness
Improvement
Measuring the dependant variable.
We measured our dependant variable with qualitative observations only, when in a lab, you should use both qualitative and quantitative observations. To create quantitative observations, we could have counted the bubbles, this might have been more difficult or inaccurate, but with it there would be numbers to use and compare.
Measurement of hydrochloric acid and metals.
When we measured the metals, we had to wait in lines and wait and in the process of pouring metals in and out of the beakers, some could have stuck to the walls, this would have made it inaccurate. To improve this problem, everyone should just have their own scale, or be patient with the scale.
Pouring the metals into the smaller test tubes from the beaker was hard.
When we tested metals such as aluminum, it was difficult to get it all into the test tube because the beaker mouth was very wide. We could solve this by changing the size of the beaker to a larger size.


​Works Cited


GCSE Science. N.p., n.d. Web. 17 Dec. 2009. <http://www.gcsescience.com/
r4-metal-reaction-with-acid.htm>.
Creative Chemistry. N.p., n.d. Web. 17 Dec. 2009.
<http://www.creative-chemistry.org.uk/gcse/documents/Sc1/reactivity.pdf>.

Chem Guide . N.p., n.d. Web. 15 Dec. 2009.
<http://www.chemguide.co.uk/inorganic/group2/reacto2.html>.