This experiment investigated how the concentration of hydrochloric acid affects the reaction time of magnesium ribbon. Five concentrations of HCl from 100% to 20% were tested, and the time taken for the magnesium ribbon to completely disappear was recorded. The results showed that higher concentrations of HCl led to faster reaction times, supporting the particle collision theory that higher concentrations provide more opportunities for effective particle collisions between HCl and magnesium.

1. Chemical
Reaction
s
Year 11
Science

2. Aim: To determine how the concentration
of Hydrochloric acid affects the time
taken for magnesium ribbon to
disappear

3. Independent variable (What we are
changing): Concentration of
Hydrochloric Acid (HCl)
Range: 100%, 80%, 60%, 40%, 20% of 2.0 M
Dependent variable (What we
measure to record for results): Time
take in seconds for magnesium ribbon to
disappear.

4. Controlled variables (What will remain
the same)
• Temperature of acid
• Volume of concentration
• Size of magnesium strip
• Same person timing

5. Equipment:
• 5 Test tubes
• 10 mL Test tube stand
• 10 mL Measuring cylinder
• Magnesium Ribbon
• 50 mL beaker
• Hydrochloric Acid 2.0 M
• Water
• Stop watch
• Thermometer

6. Method:
1. Collect 5 Test tubes, Test tube stand, 50 mL Beaker, Thermometer, Measuring
cylinder, Stop watch and Bottle of hydrochloric acid (2.0 M)
2. Collect 10 pieces of magnesium ribbon, making sure they are exactly the same
size.
3. Fill your beaker with tap water
4. Measure 5 mL of 2.0 M HCl using a measuring cylinder. Place in water bath to
keep temperature constant.
5. Add Magnesium and record the time it takes to disappear. Start recording from the
time you add the Mg to test tube and stop when it disappears (This is when the
chemical reaction has finished)
6. Record Results in table.
7. Do steps 4,5 and 6 again to test for reliability
8. Test 80% concentration. Place 4 mL of 2.0 M HCl in a test tube and 1 mL of water.
Place test tube in water bath.
9. Place Mg in Test tube and record from when you place it in the test tube until it has
disappeared. - Record results
10. Repeat steps 8,9,10 again to test for reliability
11. Repeat steps 8,9,10 and 11 for 60% concentration, 40% Concentration and 20%
concentration.

7. Milliliters of 2.0
Mol Hydrochloric
Acid
Milliliters of
Water
Concentration of 2.0 M
Hydrochloric acid in
Percentage (%)
5 mL 0 mL 100%
4 mL 1 mL 80%
3 mL 2 mL 60%
2 mL 3 mL 40%
1 mL 4 mL 20%
Concentration Table:

8. Results Table:
Time taken for Magnesium strip to
disappear (seconds)
Concentration
of 2.0 M HCl
Test 1 Test 2 Test 3 Average
100%
80%
60%
40%
20%

9. Graph Results:
Time taken for Magnesiumto dissapear in different
concentrations of 2.0 M HCl
0
20
40
60
80
100
120
100% 80% 60% 40% 20%
Percentage Concentration of 2.0 M Hydrochloric Acid
Time(Seconds)
Time

10. Conclusion: Needs to state what happened in the
results and how we know that it happened
Example: These results show the higher the
concentration of 2.0 Mol Hydrochloric Acid the
faster the magnesium ribbon disappeared and
therefore the faster the rate of reaction. The
results show this clearly with the magnesium
ribbon disappearing in _____seconds at the
100% concentration of 2.0 M Hydrochloric acid
compared to the magnesium ribbon
disappearing in ____ seconds at the 20%
concentration of 2.0 M Hydrochloric acid.

11. Justification: Explanation of why you did
what you did during the method
• I used 5 different concentrations of Hydrochloric acid so
that I can have accuracy in my data as the more tests I
complete the more data I have to review
• 1 only had one reaction going at a time to ensure that I
correctly timed the reaction
• I used the same equipment to ensure their were no
differences in the measuring
• I was the only one doing the experiment to keep the
measuring and timing of the experiment the same.
• I measured the magnesium so that they were all the
same size so that the size of Mg was not a factor in the
investigation.
• We used a water bath to keep the temperature of the
reaction the same

12. Collision THEORY

13. Discussion – Relate the finding from your investigation to
the particle collision theory of reaction:
The higher the concentration of Hydrochloric
acid the more particles there are in the 5
milliliters of concentrate to collide with the
magnesium, this means the chance of
collision is greater which mean higher
change o f effective collision. The higher
the chance of collision between the
Hydrochloric acid and the magnesium, the
faster the reaction will be completed