Factors Affecting Reaction Rates

                       Water bath at 60◦ C

Chemicals: 6M HCL

                     3M HCL

                     1M HCL

                     0.1M HCL

Procedure: We experiment with four different concentrations of HCL. Firstly, we put the different concentration of HCL in four different tubes. In each tube we put a piece of zinc and observe what happens. Then we have 1M HCL in three different tubes. In one tube we put a piece of zinc, granulated in another one and in the third tube powdered zinc. After putting these in the three tubes we observe the changes. Thirdly, we have 1 M HCL in two different tubes. One of these tubes is put in a warm waterbath and it is warmed until it reaches approximately 60◦ C. After taking it out, one piece of zinc is put in each test tube.

Results and Conclusion:

1. In the first one we observe that the reaction increases as the concentration increases. In the first tube with 0.1M almost nothing happens. In the second one with 1M we observe slight changes and small bubbles. The one with 6M of HCL is the one which reacted most vigorously. We could observe a lot of bubbling from the bottom of the tube and it dissociated pretty easily and quickly. This is because, the more concentrated the reactants the more collisions there will be per second per unit volume. So the rate of reaction increases as the concentration is increased.
2. In the second part where we have three different forms of zinc we observe different changes. In the first where we have pieces of zinc in 2M HCL almost nothing happens. We just see some slight bubbles coming up. In the next tube where we put granulated zinc we see better changes. Here the reaction happens more quickly compared to the first tube. The one with powdered zinc is the one which had the largest rate of reaction. Where we saw bubbles instantly and there formed some precipitate. An explanation to this is, in the solid substance only the particles on the surface can come into contact with a surrounding reactant. If the solid is in powdered form then the surface area increases dramatically and the rate increases correspondingly.
3. The last part where we heat one tube until 60◦ C shows the difference of rate in different temperature. As the temperature increases the particles will move faster so there will be more collisions per second. Here where the zinc is put in the warm water the reaction happens more quickly. However, the main reason why an increase in temperature increases the rate is that more of the colliding particles will possess the necessary activation energy resulting in more successful collision.

We can conclude that when the concentration, temperature and surface area is increased the reaction rate increases. In each of these tests we can also observe that as the reaction takes place in a larger concentration and surface area they get warmer as well. This proves that an exothermic reaction place here. Thus we see that concentration, surface area and temperature are factors which affect the rate of reaction.