Lab. #27 Part II Data

To Chemistry 2 Lab Students:

Some of you weren't able to finish the Part II of the experiment investigating the effect of surface area; I have modified the procedure a little bit and list the observations below:

• Modification: Use 40mL 2.0M HCl + 20 mL tap water for the acidic solution (instead of 10 mL 2.0M HCl + 50 mL water).

• Results: (You will calculate the reaction rate using the same formula on the lab sheet)

Test Tube 1 (Rolled): Reaction time is 102 sec; Observation: Was able to use the dropper to hold the rolled piece fully submerged within the solution.

Test Tube 2 (Flat): Reaction time is 50 sec; Observation: Was able to use the dropper to hold the flat piece fully submerged within the solution.

Test Tube 3 (7 pieces): Reaction time is 140 sec; Observation: Was not able to use the dropper to hold all little piece submerged, hence all the pieces stay on/near the surface with one side exposed to the air.

• Since the conditions of Test Tube 1 and 2 are similar, the effect of increased surface area should be made based on 1 and 2. Why do you think test tube 3 takes much longer time for Mg to completely react?

Dr. Liu