The effect of Hydrocholric acid on the Rate of Reaction

Method:

First I filled five different test tubes with the five different concentrations of the acid. I measured all of them to 20cm3. Then I collected five different pieces of zinc, and then weighed them on a scale. I recorded these results for later use. I made sure the temperature of the acids was the same using thermometers.  I placed each piece of zinc in a different concentration and started the stop watch. After forty-five minutes I removed each piece of zinc and dried them with tissue paper. I then measured them with the same scales I had used before and then recorded the results. I will measure the rate of reaction by working out the amount of mass lost by the zinc.

Diagram:

Equipment:

Test tubes

Hydrochloric Acid

Zinc

Measuring cylinder

Thermometer

Scale

Results:

Conclusion

My conclusion is that as the concentration of the acid increases then the rate of reaction or the amount of mass lost increases. This indicates a direct correlation between the two variables. My explanation for this would be that zinc and hydrochloric acid react when they come in contact. The weight of the zinc decreases as it reacts to form zinc chloride, so there is less zinc leftover.  So if the concentration of the acid increases this means there are more acid particles colliding with the zinc, resulting in an increase of zinc chloride and a bigger decrease of zinc.

Evaluation

Accuracy:

The accuracy of the experiment was reasonable. The scales that I used were not as accurate as possible and they showed variation when I repeated the measurements. I believe a more accurate scale could have been used if it was available to me.

Reliability:

I believe that this experiment was not very hard to carry out and that anyone could repeat this experiment and obtain the same or very close results to what I obtained. I believe my conclusion can be considered reliable because I had relatively accurate results and had no anomalies in my experiment.

Improvements:

I believe that if I had the zinc pieces of equal size and weight the results would have become much more reliable as factors such as surface area could not have affected my results. Then I think if I had left the zinc in for longer then I could have obtained more significant results reducing the chance of any anomalies. In the time I was provided I did not have time to repeat the experiment and without equal pieces of zinc these repeats would not have been very effective.  Again a better set of scales could have improved the accuracy of my measurements.

Alternate experiments:

I believe I could have changed the way I measured the rate of reaction by changing the experiment. Instead of measuring the zinc I could have measured the amount of hydrogen that was released in the reaction. I believe that if I had done this experiment my results would have been more accurate.