The Effect of Different Concentrations on the Rate of Reaction between Magnesium Ribbon and Hydrochloric Acid

Apparatus:

1. Eye protection
2. Conical flask (100 cm3) 
3. Single-holed rubber bung and delivery tube to fit conical flask
4. Gas syringe (50cm3)
5. Syringe (10ml)
6. Clamp stand, boss and clamp
7. Stopwatch
8. Electronic Scale
9. Burette
10. Measuring Cylinders
11. Knife/Scissors
12. Ruler
13. 15 cm of Magnesium ribbon
14. 50 cm3 of 1 mol dm-3 Dilute hydrochloric acid- 1M, 2M, 4M 

Method:

SAFETY: Wear eye protection throughout.

1. Measure 50 cm3 of 1 mol dm-3 hydrochloric acid using a measuring cylinder. Pour HCL acid into the 100 cm3 conical flask.

2. Set up the apparatus as shown in the diagram above.

3. Then add a 15 cm strip of magnesium ribbon to the conical flask, immediately put the bung back into the flask as quickly as you can, and start the stopwatch.

4. Record the volume of hydrogen gas given off at suitable intervals (eg every 30 seconds). Continue timing until no more gas appears to be given off.

5. Repeat with different concentrations of HCL.( 1M, 2M, 4M)

Results table:

Acid Concentration- 1 mol/dm3

Acid Concentration- 2 mol/dm3

Acid Concentration- 4 mol/dm3

Conclusion:

From my above results, it shows the greater the concentration of HCL the faster the rate of reaction. However, my results do not partially support my hypothesis as it proves that double the concentration of HCL doesn’t double the rate of reaction. The greater the concentration; the greater the amount of particles colliding together. Hence, greater the amount of successful collisions per second. Going from 1M HCL with an initial rate of reaction of 0.98 cm3/s to 2M HCL acid with an initial rate of reaction of 0.92 cm3/s, the rate of reaction has increased by about 1 time.

Evaluation:

I was precise and accurate in my measurements as I measured the acid with a measuring cylinder to the line, viewing it at eye level. I used a ruler to measure the magnesium ribbon. I also used a large amount of volume of HCL to delete any temperature changes.

• I should have repeated my experiment 3 times to have a greater significant difference between the three data’s.
• There were a few anomalous and big variations to my results table which could have been caused by escape of volume of carbon dioxide gas. Hence, I could improve the experiment by placing a shelf in the conical flask, for the magnesium ribbon, so no gas can escape.
• I can also put the conical flask in a bath to make sure there is no temperature change. Hence, making my results more accurate.
• I could put the magnesium ribbon in sand to get rid of any magnesium which has already reacted with oxygen, hence, weighing it to make sure they all have the same mass.