The aim was to become accustomed to working with the equipment and to find optimum levels of hydrochloric acid and magnesium ribbon to produce 60cm of hydrogen, a sensible amount to produce in the real experiment.

  The next procedure we carried out involved changing another variable. Having discovered what length of magnesium ribbon would produce 60cm  of hydrogen when allowed to react with 25cm  of hydrochloric acid, we then used this length of magnesium ribbon and the same amount of hydrochloric but changed the temperature of the hydrochloric acid that was allowed to react with the magnesium ribbon to see if this had any effect on the reaction by previously heating the hydrochloric acid to different temperatures using a Bunsen burner. We recorded the amount of hydrogen produced every 15 seconds using a stopwatch.

Results:

This is a word equation for the reaction between magnesium and hydrochloric acid:

       

Here is a table of the amounts of hydrogen produced when 25cm  of hydrochloric acid reacts with different length strips of magnesium ribbon:  

Here are two tables showing the rate of the reaction between 25cm  of hydrochloric acid and a 4.5cm strip of magnesium ribbon when the hydrochloric acid is heated to 40°C and 70°C respectively:

                                                                                                                                                                                                                 

                                                                                                                                       

                                         

 

Conclusion:

In the first part of the pilot experiment, we discovered that the correct length of magnesium ribbon to produce approximately 60cm  of hydrogen gas when allowed to react with 25cm  of hydrochloric acid is 4.5cm. We also became aware of the products of the reaction, magnesium chloride and hydrogen gas. We became aware of several possible faults in the method in which the results could be made inaccurate, namely that the rubber bung had to be used to seal the test tube immediately after the magnesium was dropped in to avoid any hydrogen escaping and that once the procedure had been carried out, we had to make sure the gas had been pushed out of the syringe so that it returned to its original position before the procedure could be carried out again, otherwise the hydrogen gas would remain in the syringe and thus affect the level of hydrogen in the syringe after the procedure was carried out again.

    In the second part of the pilot experiment, we discovered that the temperature of the hydrochloric acid did not affect the amount of hydrogen gas produced, but did affect the rate of the reaction, the final amount of hydrogen produced did not change but was produced in 90 seconds at 70°C and in 120 seconds at 40°C. This is because the amount of hydrochloric acid and magnesium does not change, therefore the amount of magnesium chloride and hydrogen will not change, but because the temperature of the hydrochloric acid is higher, the atoms in the hydrochloric acid will be moving faster, and therefore will collide and bond (ionically) with the magnesium atoms quicker.

    We also discovered several points to remember in the second procedure to ensure accurate, reliable results. The hydrochloric acid was heated in a small beaker and this became very hot, so we had to use tongs to pour it into the test tube. As the reaction begins to happen even more quickly when the hydrochloric acid is heated, we had to ensure also that we were ready to immediately seal the test tube after pouring in the heated hydrochloric acid and placing the magnesium in immediately to avoid the hydrochloric acid cooling.