announcements & Experiment No.6

Guys if you've seen an XpressMusic or whatever it's called (NOT touchscreen) please contact Jethro. :(

Play is on March 8, so :| :(( :o and it's being held in the 4th Floor Audi. Trying to book it...

Experiments 6-10 can be found in the 2nd Floor B-lob. P11 lang.

Experiment No. 6
Classifying Mixtures

Introduction
In this experiment you will compare some properties of starch solutions with those of a sodium chloride solution. You will also use the Tyndall effect to identify the different kinds of mixtures.

Objective
To classify the kinds of mixtures using starch mixtures and sodium chloride solution.

Equipment	Materials/Chemicals
1 filter paper 2 teaspoons, plastic 1 cent-o-gram balance 4 100mL beakers 1 funnel 1 alcohol burner 1 tripod 1 wire gauze 1 50mL graduated cylinder 1 stirring rod 1 penlight, 3 volts
	NaCl Starch water

Procedure

1. Add about 1/4 tsp. (approx 3g) of common table salt to 30mL water in a 100mL beaker. Stir until the salt is completely dissolved. Filter and set aside.
   
2. Add 1/4 tsp of starch to 30mL of water in another 100mL beaker. Stir thoroughly and place beside salt and water mixture.
   
3. Add about one teaspoon (approx 5g) o starch to 50mL water in another 100mL beaker. Stir thoroughly, heat mixture with constant stirring until boils and becomes clear. Get 10 mL of this mixture and put it in another 100mL beaker. Add enough water to make volume 30mL. Place beside other beakers. Compare the contents of 3 containers.
4. Focus the penlight on each of 3 beakers. Look at beam of light from the top of the beaker (at right angles to the beam of light). Note difference.
   

Data Results

Table 6 Effect of a Beam of Light on Mixture
Mixture	Appearance	Visibility of Dispersed Particles	Effect of Light Beam	Kind of Solution
Table salt & water
starch & water
cooked starch & water

Questions

1. Which o the mixtures can be described as homogenous? Heterogenous?


2. In which system is the path of a beam o light revealed?


3. Give at least two examples of each type of mixture.


4. Cite two uses of each type of mixture.