STUDENT INFORMATION

A chemical change is define as a change that occurs when one or more substances are changed into a new substance with its own unique and different chemical properties. To understand chemical change, you should be familiar with the two types of chemical reactions and balancing chemical equations. In this experiment you will observe the five properties of a chemical reaction and determine if a chemical change has occured. You will be working with Hydrogen Peroxide, raw liver and potatoes.

Hydrogen Peroxide is a solution that is commonly use as a disinfectant for bruises, scrapes and cuts.This solution is used to clean wounds. Going Further: Research how hydrogen peroxide was discoevered, why it is used as a disinfactant and its effects.

OBJECTIVE

In this experiment you will be able to observe, compare/contrast the chemical changes in liver and pototaes when hydrogen peroxide is added to each.

BACKGROUND

Laboratory Tips: It is important that you stay alert so that you do not miss any subtle changes that may occur. Also, be sure that the bulb of the thermometer is not touching the bottom of the test tube.You should also know the difference between endothermic and exothermic reactions

PROBLEM

Does chemical change occurs the same way in liver as in potatoes and what are the evidences that cheemical change did occur?

MATERIALS NEEDED

PROCEDURE

Part One

1. Form group of threes and assign responsiblities to each individual in your group such as a time keeper, recorder, and someone to fetch the materials.

2. The material gatherer will gather all materials and take them to the group's lab table.

3. Pour 25 ml of Hydrogen Peroxide into a 50ml beaker.

4. Place five(5) clean test tubes into a test tube rack.

5. Add five (5) ml of Hydrogen Peroxide to a clean test tube, take and record the temperature. This is your starting temperature.

6. Keeping the thermometer into the test tube add a small piece of potatoe to the test tube with the Hydrogen Peroxide .

7. Take the temperature every 30 seconds for five (5) minutes and record your reading in the data table.

8. Keep the thermometer in the test tube during the entire five (5) minutes while monitoring the change in temperature.

9.Repeat steps 4-8 three more times and record your data in the appropriate place in the data table.

10. Add up the temperatures in each column and tahe the average

11. Using the average temperatures construct a graph.

Part Two

1. Repeat steps 3-11 except that this time you will use pieces of uncooked liver instead of the raw potatoe.

2. In step six (6) and nine (9) add liver instead of potatoe.

3.Remember to record your data in the data table for the liver.

4. Remenber to use the average temperatures form the data table for the liver to construct the new grah..

DATA TABLE

Part One-Potatoe

TEMPERATURES PER 30 SECONDS INTERVALS-POTATOE

TRIALS Start 1/2 min. 1min 11/2mins. 2mins 21/2 mins 3 mins 31/2 mins. 4 mins 41/2 mins 5 mins

1

                     
2                      
3                      
4                      
TOTAL                      
AVERAGE                      

 

Part Two-Liver

TEMPERATURES PER 30 SECONDS INTERVALS-LIVER

TRIALS Start 1/2 min. 1 min. 11/2 min. 2 mins. 21/2 mins 3 mins. 31/2 mins 4 mins. 41/2 mins. 5 mins
1                      
2                      
3                      
4                      
TOTAL                      
AVERAGE                      

DATA ANALYSIS

1. Explain the didfferences between the graph results you obtained from graphing the temperature changes in the reaction with the liver and that of the potatoe.

2. Which of the two graphs most likely depicted an endothermic or exothermic reaction?

FOLLOW-UP ACTIVITIES

a) Improving balancing equation skills.

Questions
Fill in the blanks below as you go though the game. This is so I have a record that you did your assignment.

1. _____ Fe + _____ S --> _____ FeS

2. _____ H2 + _____ Cl2 --> _____ HCl

3. _____ Mg + _____ O2 --> _____ MgO

4. _____ O2 + _____ H2 --> _____ H2O

5. _____ HgO + _____ Hg --> _____ O2

6. _____ Ca + _____ H2O --> _____ Ca(OH)2 + _____ H2

7. _____ CH4 + _____ O2 --> _____ CO2 + H20

8. _____ Na2O2 + _____ H2SO4 --> _____ Na2SO4 + _____ H2O2

9. _____ N2 + _____ H2 --> _____ NH3

10. _____ Al + _____ O2 --> _____ Al2O3

11. _____ KMnO4 --> _____ K2O + _____ MnO + _____ O2

Draw the molecules just like the program did to figure out the answer to #12 and #13.

12. _____ Na + _____ H2O --> _____ NaOH + _____ H2


b) Review of chemical reactions and chemical change.

 

 

 

 

 

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