Rabu, 12 Mei 2010

[duniaSMA] Making Colloid


I. Instrument and Material
Instrument : Chemical glass, burner device, tripod and gauze, tubes, a tube’s rack,
pipette, spatula mortar, and pounder.
Materials : - Distilled water
- Saturated solution of FeCl3
- Sugar and Sulfur Powder
- Cooking oil, white egg, salt, some detergent, lemon water
II. Activity Step
MAKING IRON (III) HYDROXIDE SOL AND SEAWEED GELATINE SOL
Purpose : Making and monitoring how to make Fe(OH)3 sol and gelatine sol
Method : Using by condensation method
  1. Making Iron (III) hydroxide sol
    1. Put 25 ml of distilled water into a chemical glass and heat it.
    2. Add about 20-45 drops of saturated FeCl3 solution then stir slowly while keeping in it heat
    3. Stop heating when solution begins to be brown red in colour
    4. Observe the change
  2. Making Seaweed gelatine sol
    1. Put about 2 grams of seaweed gelatine into reaction tube
    2. Contains water at half tube
    3. Heat the solution then stir it until the gelatine dissolved
    4. Cool the tube.
MAKING SULFUR SOL
Purpose : Make colloid with mechanic dispersion way
Method : Using by Dispersion method
  1. Making Sulfur sol
    1. Crush 1 spoonful of sugar and 1 spoonful of sulfur powder in a mortar by using powder
    2. Take half of the sugar-sulfur mixture
    3. Add into the mixture 1 spoonful of sugar and crush mixture again
    4. Do step above twice
    5. Take 1 spoonful of the last crushing product then put it into water
    6. Observe the mixture produced
    7. Take sugar and sulfur powder which are not yed crushed, then put them into 50 ml of distilled water.
    8. Observe the mixture produced and compare it with the mixture of sugar-sulfur which have been crushed
PROVE SHEET
No
Experiment
Observation
1.
Making Fe(OH)3 sol
Happened colloid
2.
Making seaweed gelatine
Change be jelly
3.
Making sulfur sol
Happened colloid
THE PROBLEM
  1. What are the phenomena which you can observe in making colloids by using those two methods?
In first method, we can saw the solution of Fe (OH)3 mixed with water and happened colloid. We call Iron (III) hydroxide sol and we can saw the solution of seaweed gelatin mixed with water change be jelly. We called Seaweed Gelatin Sol.
In second method, we can saw the sugar-sulfur mixture after crush and mix with water, happened colloid. But sugar-sulfur mixture which are not yet crushed and mix with water, didn’t happen colloid, the sulfur fly and swing in water surface.
  1. What is the function of sugar in experiment making sulfur sol?
Sugar has function as a substance to mix sulphur with water
  1. How to purity those colloid above?
Solution
Color
Observation


Initial
After mixture
Cooling
Fe(OH)3
Brown
Brown
Brown red
Brown red
Seaweed
White
Turbid
Turbid
Jelly
Sulfur sol
Yellow
Turbid
Turbid
Turbid
  1. Write down the reaction of making Fe(OH)3 sol?
FeCl2 + H2O Fe(OH)3 + HCl
CONCLUTION
INTRODUCE COLLOID SYSTEM
  1. Making Oil Emulsion in Water
    1. Prepare 4 tubes and put them on rack, pour 3 ml water and 3 ml cooking oil in each tube
    2. Put 1 spoonful of salt, egg white, lemon water and detergent into each tube
    3. Shake all tubes and let it for a while
    4. Observe the result
    5. Write down your observation result
PROBLEM
  1. What happens when you mix water and oil?
Water and oil did not mix.
  1. What happens when you put detergent into water and oil mixture?
Water and oil can mixed because the detergent is suspension system so can make the water and oil mix.
  1. What substance that can function as emulsifier in experiment?
Detergent have function as emulsifier in experiment
  1. What substance that cannot function as emulsifier in the experiment above?
Egg and salt cannot function as emulsifier in that experiment
  1. What is your conclusion from the experiment above?
Detergent have function s-emulgator –substance which can make stabile colloid—
and the egg and salt cannot function as emulsifier in that experiment

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