SNC 2D Chemistry Lab – Rates of a Reaction

Name:______

Introduction:

The rate of a reaction is the speed at which a reaction happens. Some reactions take hundreds, maybe even thousands of years while other can happen in less than one second. The rate of reaction depends on the type of molecules that are combining.
There is another big idea for rates of reaction called collision theory. The collision theory says that the more collisions in a system, the more likely combinations of molecules will happen. If there are a higher number of collisions in a system, more combinations of molecules will occur. The reaction will go faster, and the rate of that reaction will be higher. Factors which affect this rate include:

·  Concentration: If there is more of a substance in a system, there is a greater chance that molecules will collide and speed up the rate of the reaction. If there is less of something, there will be fewer collisions and the reaction will probably happen at a slower speed.

·  Temperature: When you raise the temperature of a system, the molecules bounce around a lot more (because they have more energy). When they bounce around more, they are more likely to collide. That fact means they are also more likely to combine. When you lower the temperature, the molecules are slower and collide less. That temperature drop lowers the rate of the reaction.

·  Surface Area: When you expose more of the surface, you expose more molecules and increase the chance of a collision

Purpose: Verify that concentration, temperature, surface area affect the rate of a reaction.

Materials

Test tubes, test tube rack, magnesium powder, magnesium turnings, 1M HCl, 0.1 M HCl, ice bath, dispensing container, pipette

Part 1. Surface area

Procedure

1. Obtain 1 piece of magnesium turnings and mass the reactant using the dispensing container.

2. Place the sample in a test tube.

3. Obtain an equivalent mass of the magnesium powder using the dispensing container. and place it in a second test tube.

3. Using a 5 ml pipette, transfer 2 ml of 1 M HCl to each test tube.

4. Complete the table observing the time required for the reaction to occur.

Observations

Sample A

Trial / Time to react ( ) / Description of the reaction
1M HCl and
magnesium turnings
1M HCl and
magnesium powder

Part 2. Concentration

Procedure

1. Obtain 2 pieces of similar sizes of magnesium turnings and place each in a separate test tube.

2. Using the pipette, transfer 2 ml of 1 M HCl to one test tube and 2 ml of 0.1 M HCl to the other test tube.

3. Complete the table observing the time required for the reaction to occur.

Observations

Sample A

Trial / Time to react ( ) / Description of the reaction
1M HCl and
magnesium turnings
0.1M HCl and
magnesium turnings

Part 3. Temperature

Procedure

1. Transfer 2 ml of 1M HCl to two test tubes.

2. Place 1 test tube in the ice bath and hold the other test tube in your hand for 3 minutes.

3. Quickly place 1 piece of magnesium turnings of similar size in each test tube.

4. Complete the table observing the time required for the reaction to occur.

Observations

Sample A

Trial / Time to react ( ) / Description of the reaction
1M HCl at body temperature and magnesium turnings
1M HCl from ice bath and
magnesium turnings

Questions

1.  Write the word equation for this single displacement reaction. Recall that metals like to react with non-metals.

2. Write the skeletal equation for this reaction.

3. Write the balanced chemical equation for this reaction.

4. What was the most surprising observation from this lab?

Conclusion (answer the purpose)