Rates:
The reaction rate speed can be changed to go faster or slower if you change the temperature and the mass of the product. If the mass of the product is a lot then it will take the magnesium to take longer to react with the hydrochloric acid and if there is a little mass it should be quicker.
In order for the Magnesium and acid particles to react together, they must:
- Collide with each other
- The collision must have enough energy
A chemical reaction can only occur between particles. When they collide (hit each other). Particles may be , or . There is a minimum amount of energy which colliding particles need in order to react with each other. If the colliding particles have less than this minimum energy then they just bounce off each other and no reaction occurs. This minimum energy is called the . The faster the particles are going, the more energy they have. Fast moving particles are more likely to react when they collide. You can make particles move more quickly by heating them up ().
As you can see from the diagrams at the before and after stage, this shows what happens to the particles when they collide into each other. The after pictures show what particles they form and also you can see the hydrogen gas.
Resources and Equipment
Metal: Magnesium/ 1cm ribbon*10
Hydrochloric Acid:
Test Tube = 10
Measuring Cylinder
Stop Clock
Variables
Input : the concentration of the acid
Out put : How long it takes for the magnesium to react.
Controlled:
- The same quantity of Hydrochloric acid
- The mass of the metal
- Constant temperature
- Surface area of the metal
- The volume of the acid
Fair Test:
- Constant temperature
- Same volume of hydrochloric acid
- Same mass of magnesium
Plan
Method
- Get the magnesium ribbon (1cm)
- Get the test tubes (10)
- Put the magnesium ribbon in the test-tube, A piece of magnesium ribbon in each test-tube
- Measure 2cm oh hydrochloric acid with the measuring cylinder
- Add the 2cm of hydrochloric acid to the test-tube 1 with 0.2 of hydrochloric acid
- Time the reaction, until the magnesium dissolves
- Repeat the staged and this time with acid:
- 0.4M
- 0.6M
- 0.8M
- 1.0M
- Repeat stage 4 and 5 to get two sets of results
Prediction:
I predict that magnesium will react the quickest in 1.0m concentration of hydrochloric acid; therefore magnesium will react the slowest in 0.2m concentration of hydrochloric acid. This means that the stronger the concentration the quicker the magnesium will react, the weaker the concentration the slower the magnesium will react.
Results
From my results it clearly shows that my prediction was correct. 0.2M being the slowest and 1.0M being the quickest.
Analyses
From my results I can see that my prediction was correct. The stronger the concentration/morality of acid the quicker the reaction will occur. I predicted that if the concentration of reactants is stronger than the rate of reaction will occur more quickly. This is because it increases the amount of particles; the molecules of the other reactant can collide with. According to my evidence there is a strong line of correlation, the higher the molarity of acid the faster the rate of reaction. This is why the line of best fit goes into a negative correlation. 1.0m of acid reacted the fastest of times 1.7 (1st Reading), 2.1 (2nd Reading) and 1.9 (average). 0.2 reacted the slowest as it is the weakest concentration, times of 23.4(1st Reading), 25.6(2nd Reading) and 24.5(Average).
Conclusion
My prediction was correct, the stronger the concentration the faster the reaction will occur e.g. 1.0m: 1.7 and 0.2m: 23.4. Therefore this shows that hydrochloric acid reacts well with magnesium even if it’s not the strongest concentration.
Evaluation
My experiment was a fair test, this is because I made sure throughout my experiment nothing was changed other than the molarity of the acid. I didn’t increase or decrease the temperature; I didn’t change the size, the weight or the type of metal that I used throughout my experiment. Also I made sure the amount of acid stayed the same. Throughout my experiment I suffered some trouble like the timing intervals; might have been wrong because by the time someone said stop, it passed a few seconds and the reading can’t be exactly 2 minutes. This is why we done the experiment twice to get a more accurate reading. We used the result to plot a graph (Average result).I measured the acid making sure that they were not over or under the amount required. I think that all my results were accurate; this is because I didn’t have any anomalous results on my graph; there is a strong line of correlation, the higher the molarity the faster the rate reaction. This is why the line of best fit goes into a negative correlation. From my graphs you can see that my prediction was correct, the higher the concentration of hydrochloric acid the faster the time it took the magnesium ribbon to disappear. My graph was good and there didn’t seem to be any points out of place (anomalous) to the line of best fit. There were no anomalous results; I carried out the experiment as accurately as possible. The evidence I gathered was reliable and efficient it supported my conclusion. The procedure used was good because it was as accurate as it could be, I used 10 test-tubes for each concentration and calculating an average which added to the accuracy of the result. I think that my results are correct as I carried out the experiment twice and I carried out the experiment as accurately as I could.
Extension
If I choose to, I would change the experiment by changing the variables of concentration to temperature and investigate how this affects the rate of reaction, because the rate of reaction is faster at high temperature. Or maybe I would keep the temperature constant. When the temperature is increased the energy of the particles increases, they move faster and collide more often this increases the rate of reaction. As the particles have more energy, they are most likely to collide and form products. The molecules of reactant gain kinetic energy and more quickly and violently as more heat is given to them.
Further Investigation
To further my investigation I will use longer ribbons of magnesium (I would use about 5-10cm of ribbon) to see if it would take longer to disappear in the concentration. I will use the more concentration (about 20ml) of hydrochloric acid but the same molarity of 0.2M-1.0M
Another way to further my investigation is to change the metal being used and also change the acid. I will change the acid to sulphuric acid. For the metals I would use 8 different metals which are:
- Copper
- Lead
- Tin
- Magnesium
- Aluminium
- Zinc
- Iron
- Nickel
From the 8 metals I will see which one reacts the fastest and use that metal, I predict magnesium will react the quickest. (Preliminary work). From there I will carry out nearly the same experiment that I conducted with hydrochloric acid and magnesium but instead I will use more concentration of acid, use a catalyst and a gas syringe. I will do the experiment two times to get accurate results.
Method
- Get the magnesium ribbon (cm)
- Get the test tubes (10)
- Put the magnesium ribbon in the test-tube, A piece of magnesium ribbon in each test-tube
- Measure 20cm of sulphuric acid with the measuring cylinder
- Add the 20cm of sulphuric acid to the test-tube 1 with 0.2 of hydrochloric acid
- Time the reaction, until the magnesium dissolves
- Repeat the stages and this time with acid:
- 0.4M
- 0.6M
- 0.8M
- 1.0M
- Repeat stage 4 and 5 to get two sets of results
This is the, method I will be using to conduct my further investigations.
