What Factors affect the rate of reaction between Magnesium Ribbon & Hydrochloric Acid

Experiment Plan/Aim:

I am going to find out what factors affect the reaction between Magnesium Ribbon & Hydrochloric Acid. More specifically I am changing the concentration of acid to find out if that has an affect on the reaction. The experiment will be a safe experiment as I will make sure that I am standing up not sitting down, so if the acid spills then I can easily move away. If people are wearing ties or have long hair then their ties should be tucked in & hair tied up, safety glasses should also be worn at all times & ties tucked in & any papers & pens should be removed from the desk while doing the experiment. Bags will be put under the desk so as you can't trip over them.

The test will be made sure it is a fair test, as I will keep all the variables, except one the same. For example the mass of the magnesium & the volume of acid will be kept the same, but the concentration of the acid will change. I will also be keeping the heat the same. The acid will be at room temperature for all experiments. Each concentration of acid will be timed 3 separate times.

These are the measurements/amounts I will be using:

Volume of Acid in each test tube - 10cm3

Mass of Magnesium used in each test tube- 0.01g

Concentration (molecules per litre) - 2.0

1.0

0.75

0.50

0.25

Prediction:

I predict that the higher the concentration the faster the Magnesium Ribbon will react & dissolve. I predict that because the higher the concentration of acid, means the more moles per litre. The more molars, the more acid, which means the more reactive the acid will be when Magnesium will be placed in the test tube. As I am doubling the concentration of acid each time, I think the time of reaction will be roughly doubled as well. I think the times will be doubled because if you have 0.25 molecules of acid, double its strength of acid is 0.50 molecules. So if it is double the acid strength, the reaction should be doubled time as well.

Equipment:

I will be using this equipment to carry out my experiment:

• Magnesium Ribbon (1 cm3 length)

• Hydrochloric Acid

• Beaker

• Safety Glasses

• Stopwatch

• Measuring Cylinder

• Test tubes

• Test tube rack

Diagram of Experiment:

Method:

5 test tubes were put into a test tube rack. The same amount of Hydrochloric Acid was poured into one test tube, then a strip of magnesium was put into the tube. Then the timer was started & when the reaction stopped (the bubbling stopped or the ribbon dissolved) the timer was stoped & the result recorded. This was repeated 3 times, then a different concentration of acid was used, but the same method applied.

Results:

(Timed results example - 18.1221 would mean, 18 minutes, 12.21 seconds)

Volume Of Acid

Mass of Magnesium

Concentration of Acid

Exact Time

1st 2nd 3rd

0cm3

0.01g

2.0

.23 45 .2572 .1878

"

"

.0

.3163 1.2723 1.3065

"

"

0.75

6.339 6.3467 6.29 12

"

"

0.50

0.2439 10.2298 10.989

"

"

0.25

8.1421 18.2312 18.1778

Results to One Rounded Decimal Place.

Times to 1.dp & Averages

st 2nd 3rd Average

.20 .30 .20

1.30 1.30 1.30

6.30 6.30 6.30

0.20 10.20 11.00

8.10 18.20 18.20

Graphs

Conclusion:

My graphs show that my predictions were right. The more concentrated the acid, the faster the reaction rate. My graph shows this because the steeper the line on my graph gets means the reaction was getting faster. The results were sort of how I predicted, roughly doubling speed if the acid strength was doubled, but there was a difference which I didn't notice before the experiment.

There was an odd acid strength 0.75, which didn't double. That strength was used in between 0.50 & 1.00 acid strength. Therefore the reaction time for 0.50 did not double for the acid strength of 0.75.

Although, the reaction time was roughly in between the reaction times of 0.50 acid strength & 1.00 acid strength.

Evaluation:

The results are accurate as the experiment was made sure it was all fair testing. Although the whole experiment could've been done at a slower pace, as it seemed the experiment was rushed. Things like room temperature did not affect the experiment as there wasn't a dramatic change in the weather & the whole experiment was completed in one day.

I don't think the results would've changed much if the room temperature was to change anyhow as all of the acid would've still been the same temperature.