1. Mixtures

2. Review From last class…?
Did you.. Complete the worksheet on mixtures and pure substances?
Put your name on it?
Put it in the pass in bin?

3. Mixtures

4. Complete the PRE-LAB portion of the lab sheet
What is a mixture?
What does homogeneous mean?
What does heterogeneous mean?
What type of mixture is a…Solution?...Suspension?...Colloid?
What is the Tyndall effect?
What does transparent mean?

5. Mixtures Lab You will be working at your tables
Each group will receive a magnifying glass, a microscope and 4 different mixtures
You will be required to look at each using the naked eye, magnifying glass and the microscope and draw conclusions whether the liquid is a heterogeneous or homogeneous mixture and whether it is a colloid suspension or solution
You will also have to draw pictures to show what you saw while doing each

6. Step 1 At your table- label each of the test tubes: Milk and Water
Starch and Water
Oil and Water
Food Coloring and Water
Milk + water
Oil + water
Food coloing + water
starch + water

7. Step 2: Make the mixtures according to the table:
Make sure each is mixed thoroughly (put thumb over top of test tube and shake)
Mixture
mL of Water
Add to Water
1. milk
5.0
5.0 mL of milk (tim’s single cup)
2. starch
10.0
1/8 tsp of starch *Ms Carter will add*
3. oil
8.0
2.0 mL (1/2 tsp) of cooking oil *Ms Carter will have*
4. food coloring
2 drops food coloring

8. Step 3:
Look at the milk, starch, oil and food coloring mixture with the naked eye and draw what you see in the data table

9. Step 4:
Look at the milk, starch, oil and food coloring mixture with the magnifying glass and draw what you see in the data table

10. Step 5:
Look at the milk, starch, oil and food coloring mixture with the microscope and draw what you see in the data table
Wet mounts (slides) have been set up for you at the microscopes
Each table will get a turn to go up and look at each of the 4 tubes (I will inform you when to go)
While the other groups are looking you will be trying the next step (light beam for Tyndall Effect) and answering conclusion questions

11. Step 6
Use a flashlight (your cell phone flash light will work well) and shine it through each mixture in a dark box or darkened room.
A solution will not scatter light,
a colloid will scatter light (you will be able to see the flashlight beam travel through the mixture)
a suspension may scatter light, but the light beam will not be transparent.
Record your observations for each mixture in the Data Table.

12. Conclusion Questions
Fill in the rest of the data table on the lab sheet
On a piece of looseleaf that you will attach to the lab, answer the following questions:
How did you decide if mixture was heterogeneous or homogeneous?
How did you decide if a mixture was a colloid or a suspension?
Which mixture was the toughest to distinguish?
Which mixture was the easiest to distinguish?
Find one more example of: a solution, a colloid, a suspension and a mechanical mixture that you could test using the same procedure.
2 sources of error that could have occurred during the lab.
Make sure you have completed the Pre-Lab Definitions

13. Clean Up
One person from each group should bring up test tubes and empty into the “Waste” Container
Bring tubes back to station, add more clean water from container, shake and pour into “Waste” container again
Put all test tubes in rack and place on trolley at front of class
Wipe down table with Lysol wipe once finished