Plan
For this experiment I will need the following equipment:
- Conical flask
- Stop clock
- Sulphuric acid
- Magnesium strips
- Gas syringe
The sulphuric acid concentration will be in decreased by 10ml every time the experiment is carried out, and to compensate for the lost sulphuric acid water will be added, but the total content will be the same throughout the experiment, which will be 50ml. The concentration follows as in the table below:
Each experiment will be carried out twice and the results will be averaged. After gathering the results, they will be plotted on as a graph to represent the data obtained.
The apparatus will be set up as shown in the diagram below:
Fair test
In order to make it a fair test the following must be carried out
- The magnesium strips used, must be o the same length
- The acid must be measured carefully
- All apparatus used must be kept and used for each experiment
- One person must view the end of the experiment and record the time displayed on the stop clock
- The temperature of the acid must be at room temperature.
Method
-
Take a conical flask and add 50 ml of sulphuric acid
- Prepare stop clock and
- Add magnesium strip to the acid
- Put cork attachment of gas syringes into the conical flask
- Start stop clock
- Observe the
- Record time for every 20 ml of gas collected
- Stop the stop clock when the experiment is over.
- Note time in results table
- Repeat experiment for the rest of the concentrations.
Prediction
From my background information, I can predict that the higher the concentration of sulphuric acid, the higher the rate of reaction will be, as they are directly proportional to each other. The reason I predict this is because of the collision theory which says that the more higher the concentration the higher the amount of particles, which increases the probability of a successful collision as the particles are more likely to collide with each other. If the amount of Successful collisions increases, the rate of reaction also increases.
Results
(1)
(2)
Averaged Results
Calculations
RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
RESULTS 1
(1) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
30
= 3.33
(2) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
35
= 2.86
(3) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
115
= 0.87
(4) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
151
= 0.66
(5) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 80
588
= 0.14
RESULTS 2
(1) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
36
= 2.78
(2) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
42
= 2.38
(3) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
121
= 0.83
(4) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
130
= 0.77
(5) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 80
611
= 0.13
AVERAGED RESULTS
(1) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
30
= 3.33
(2) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
38.5
= 2.60
(3) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
138
= 0.73
(4) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 100
140.5
= 0.71
(5) RATE OF REACTION = AMOUNT OF GAS GIVEN OFF
CM 3 / SEC TIME TAKEN
= 80
619.5
= 0.13
- There was no reaction for experiment number 6 because there was no acid present, so therefore there was no reaction. As water particles don’t react with magnesium in the same way sulphuric acid does.
Now that I have retrieved the results successfully I am now going to display the results graphically in a graph to interpret, determine any patterns and anomalies etc. The graph is displayed on the following page.
Conclusion
I can conclude that if you double the concentration of the acid the reaction rate would
also double, this is because the ions are closer together in a concentrated solution. The
closer together they are, the more often the ions collide. The more often they collide, the
higher the chance of a reaction between the magnesium and the sulphuric acid. Also
because there are more particles in the solution which would increase the likelihood that
they would hit the magnesium so the reaction rate would increase. The graph gives us a
good device to prove that if you double the concentration the rate of reaction doubles. If
you increase the number of particles in the solution it is more likely that they will collide
more often. In the reaction, when the magnesium hit the acid, it fizzed and produced
many bubbles it was silver in colour (which is one magnesium’s physical properties silvery
white metallic element), the activation energy of a particle gets higher with heat, the
particles which have to have the activation energy are those particles which are moving,
in the case of magnesium and sulphuric acid, it is the sulphuric acid particles
which have to have the activation energy because they are the ones that are moving and
bombarding the magnesium particles to produce magnesium sulphide.
Evaluation
I believe that the experiment was successful but some of the results were unreliable. The some results have been ignored in this investigation .the experiment was designed well but there were a few problems. Although the initial rate of reaction (which is what I am concerned with in this investigation) seemed to fit a trend, the rate of reaction curves of some on the graph crossed. This could have been because some of the magnesium had corroded forming a magnesium oxide layer, which would have affected the rate of reaction.
Other factor which could have given me unreliable results could have been that the gas syringes were wet causing them to jam and so not giving correct results or that the bung was not placed on the top of the side arm tube fast enough which allowed gas to escape. I conducted all experiments for each temperature at the same time to save time.
To improve the experiment I would find a way of attaching and releasing the magnesium inside the side arm tube above the acid (with a bung at the top of the side arm tube) so that the magnesium could be dropped into the acid without any gas being lost.
Additional work, which could be carried out, is to repeat the experiment using, a wider range of concentrations. The investigation could also be extended to investigate other factors affecting the rate of reaction such as the particle size of the magnesium.
