Name:________________________________
Date:___________
Chemical Reactions
Many reactions produce gases which can help identify the products involved. It is
therefore important to be able to test for several common gases. We will be practicing
two tests for two different gases: Hydrogen and Oxygen. To test for hydrogen a small
sample can be ignited. Hydrogen will make a squeaky pop when lit in air, care needs to be
taken with this test as large amounts of hydrogen are very explosive in air. Oxygen
supports combustion so a good method of testing for oxygen is to take a glowing splint
and place it in a sample of gas, if it re-ignites the gas is oxygen. This is a simple but
effective test for oxygen. There are sometimes confusions as the splint can create a
pop very slightly on re-ignition, which sometimes is mistaken for hydrogen. A hydrogen
pop is much more violent, sometimes enough to completely extinguish the splint. These
will be used to verify the products in the equations for Workstation 1 and 4.
In Workstation 4 we will also be using an enzyme to speed up the reaction. An
enzyme is a protein that speeds up or slows down a specific chemical reaction in an
organism. A good rule of thumb is to remember that enzyme names end in “-ase”. This
will help in identifying enzymes in further readings. Generally enzymes are catalysts.
Hydrogen peroxide is a toxic chemical that is produced in many organisms during
metabolism. Organisms must get rid of this toxin to survive. One reaction turns the
hydrogen peroxide into water and oxygen. The enzyme that helps with this reaction is
called catalase. This is found in both plants and animals. In Workstation 4 we will use
potatoes as our catalase source.
Purpose: To observe different type of chemical reactions.
To balance chemical equations.
Procedure:
1. You will be assigned to a workstation at which you will begin the lab.
2.
3.
4.
5.
6.
Follow the instructions at the workstation.
When finished, clean the equipment you used and leave the workstation as you found it.
Return to your desk and complete the data table for that workstation.
At your teacher's direction, move to the next workstation.
Repeat steps 2-5.
Workstation 1
HCl and Mg
1. Light the Bunsen burner
2. Add 5-8 ml of HCl to a test tube in a test tube rack.
3. Drop a 2-cm piece of Mg ribbon into the test tube.
4. Place your thumb over the mouth of the test tube.
5. When the reaction appears to have ended, light a wood splint and quickly test
the collected gas for flammability by holding the burning splint near the mouth
of the test tube when you remove your thumb.
6. Record your observations.
7. Clean your workstation. Leave it as you found it.
Observations
Type of reaction
Equation
___HCl + ___Mg -------->
____MgCl2 + ____H2
Workstation 2
Cu and O2
1. Light the Bunsen burner.
2. Hold a piece of copper with a pair of tongs.
3. Place the copper in the flame.
4. Record your observations.
5. Clean your workstation. Leave it as you found it.
Observations
Type of reaction
Equation
___Cu + ___O2 ----------> ___CuO
Workstation 3
CH4 and O2
1. Light the Bunsen burner.
2. Record your observations
3. Clean your workstation. Leave it as you found it.
Observations
Type of reaction
Equation
___CH4 + ___O2 --------->
___H2O +
___CO2
Workstation 4
Hydrogen Peroxide and Potato
1. Add approximately 5mL of hydrogen peroxide to a test tube.
2. Put 2 or 3 shavings of potato into the test tube.
3. Place your thumb over the top of the test tube.
4. Observe the reaction for 2-3 minutes.
5. Record observations.
6. Clean workspace and throw potato in the trash.
Observations
Type of reaction
Equation
___H2O2 ----------> ___H2O + ___O2
Workstation 5
Zn and CuSO4 (aq)
1. Add small piece of zinc to a test tube.
2. Add approximately 5ml of CuSO4 to the test tube.
3. Observe the reaction for 2-3 minutes.
4. Record your observations.
5. Clean your workstation. Leave it as you found it.
Observations
Type of reaction
Equation
___Zn + ___CuSO4 ----------> ___Cu + ___ZnSO4
Workstation 6
CuCl2 and Na2CO3
1. Add about 3ml of CuCl2 to a test tube.
2. Add about 3ml of Na2CO3 to a different test tube.
3. Slowly pour the contents of Na2CO3 to the test tube with CuCl2.
4. Gently swirl the test tube to fully mix both contents.
5. Record observations.
6. Clean up workstation and leave it the way you found it.
Observations
Type of reaction
Equation
___CuCl2 + ___Na2CO3 ----------> ___CuCO3 + ___NaCl
Conclusions:
1. What was the purpose of this lab?
2. What does it mean when an equation is balanced?
3. What are the signs of a chemical reaction that you saw in each Workstation?
4. What type of reaction did you see at Workstation 1? What observations did you
see that told you this?
5. What type of reaction did you see at Workstation 2? What observations did you
see that told you this?
6. What type of reaction did you see at Workstation 3? What observations did you
see that told you this?
7. What type of reaction did you see at Workstation 4? What observations did you
see that told you this?
8. What type of reaction did you see at Workstation 5? What observations did you
see that told you this?
9. What type of reaction did you see at Workstation 6? What observations did you
see that told you this?
10. What are some possible sources of error that could have occurred during the lab?