Idea Transcript
Magnesium and Dilute Hydrochloric Acid Practical Aim: To investigate the reaction between magnesium and dilute hydrochloric acid. Prediction: The more concentrated the acid is, the faster the magnesium ribbon will dissolve. This is because the rate of reaction depends on how frequently the molecules of the reacting substances collide. A more concentrated substance has more molecules for a given volume than a more dilute substance. Because there are more molecules about, the frequency of successful collisions is greater, and the reactions happen faster. Prediction Graph:
A Prediction Graph to show how the concentration of the dilute
Rate of Reaction (1/Time)
hydrochloric acid effects the time taken for the magnesium to fully dissolve
Concentration (M)
Variables: Dependant Variable: The time it takes for the magnesium to fully dissolve. Independent Variable: Concentration of the dilute hydrochloric acid. Controllable Variable: Volume of hydrochloric acid, length of magnesium, same type of test tube. Apparatus List: -
Test Tube x5
- Stopwatch x1
-
Test Tube Rack x1
- Lab Coat x1
-
Magnesium Ribbons (3cm) x5
- Dilute Hydrochloric Acid (30ml) (0.1, 0.2, 0.5, 1, 2)
- Lab Goggles x1
Diagram: TEST TUBES
TEST TUBE RACK
MAGNESIUM RIBBON
DILUTE HYDRCHLORIC ACID
STOPWATCH
BUBBLES
Method:
1. Wear safety equipment such as lab coat and lab goggles. 2. Get the required equipment listed above. 3. Next place the five test tubes in the test tube rack. 4. Using a measuring cylinder, measure out 30 millimeters of each concentration of dilute hydrochloric acid. 5. Pour it in all five test tubes. 6. Make sure to reset the stopwatch to zero. 7. You could label the concentration to make sure you don’t forget which tube has how much concentration. 8. Then one at a time, place the magnesium ribbon in any of the test tubes. 9. Once you drop it in the acid, start the stopwatch. 10. You will stop the stop watch and record the results when the magnesium ribbon is fully dissolved. 11. Do this for the other four test tubes. 12. If you have enough time, repeat the whole experiment again for reliability.
Results Table:
A Results Table to show how the concentration of the dilute hydrochloric acid effects the time taken for the magnesium to fully dissolve Concentration of Acid (M)
TIME TAKEN FOR THE MAGNESIUM TO FULLY DISSOLVE IN THE ACID (MINUTES) 1st Try
2nd Try
3rd Try
Average
0.1
+ 50
+ 50
+50
50
0.2
+ 40
+ 40
+ 40
40
0.5
+ 40
12.22 sec
+ 40
30.74
1
4.21 sec
3.47 sec
4.02 sec
3.9
2
0.58 sec
1.14 sec
1.05 sec
0.92
Rate of Reaction: 0.1 M = 1/50
1 M = 1/3.9
0.2 M = 1/40
2 M = 1/0.92
0.5 M = 1/30.74 Results Graph:
A Results Graph to show how the concentration of the dilute hydrochloric acid effects the time taken for the magnesium to fully dissolve
Conclusion: In conclusion, according to my results, there was a big gap between the result of concentration 0.5 and concentration 1; this is because concentration 0.6, 0.7 so on was not included in the experiment. Moreover, I found out that the acid with the highest concentration react the fastest; this supports my prediction. As I said in my prediction, it react the fastest because a more concentrated substance has more molecules than a dilute substance. Because there are more molecules about, the frequency of successful collisions is greater, therefore the reactions happen faster. Evaluation: Despite the collision of two other people joining my experiment, the practical went brilliantly well. Although it was quite confusing, we communicated and every obstacle in our way was removed. However, because we did not do the same exact practical before, we did not expect the magnesium to take more than one hour to fully dissolve in concentration 0.1 and 0.2; therefore we did not get accurate results for them and we had to modify our plan. Evaluation Table:
!
!
The concentration of 0.1
I could not get an
I could modify my plan, or
and 0.2 took more time
accurate result.
I could just wait for it to
than we expected.
fully dissolve, if we have the time.
A little amount of water
It would be completely
Use another boiling tube
could have been mixed
acid so it might have
but the same type.
with the acid
effected the reaction