Colloids and Their Properties Flashcards
title of experiment 3
Colloids and Their Properties
two phases of colloids
continuous phase (dispersion medium)
discontinuous phases (dispersed phase_
Contains particles larger than the solute particles of a true solution; homogenous to the naked eye
colloidal system
examination of a colloid under the microscope will show particle movement called
Brownian Movement
When subjected to a beam of light in a darkened room, colloids show
Tyndall effect
example of liquid colloidal system
milk
protein in milk
casein
casein contains
negative charges on the particle surface which prevents particles from coalescing
what will happen if acetic acid is added to milk
the H+ released by acetic acid neutralizes the negative charges on the particle surface, causing curd formation
different properties of colloids help in understanding
- proteins
- foods
- medicines
- enzymes
- fats
Colloid play an important role in
- digestion
- metabolism
- most all phase of physiological processes
materials/reagents needed for the formation of curd
- 0.1 M CuSO4
- 10% skim milk mixture
- 3 M HAc
Test Tubes and their contents
1 - 4 mL 0.1 CuSO4
2 - 4 mL 10 % skim milk mixture
3. - 4 mL skim milk 3 M HAc
what tube is there an evidence of curd formation?
3 - skim milk and 3 M HAc
which particles are large enough to be retained by filter paper?
particles of skim milk and 3 M HAc mixture
You filtered each contents of tubes 1 and 2, did the dialysis set up, what happened?
- blue color outside the dialysis bag of CuSO4 filtrate indicates copper ions
- there’s turbidity outside the dialysis bag of skim milk
formation of protective colloids reagents (1)
10 drops 0.2 M K2Cr207
4 mL distilled water
10 drops 0.04 M AgNo3
after mixing 10 drops 0.2 K2Cr207 , 4 mL distilled water , 10 drops 0.04 AgNo3 what was the product
silver dichromate (there’s a precipitate)
formation of protective colloids reagents (another test tube)
10 drops 0.02 M K2Cr2O7, 1 mL gelatin solution, 10 drops 0.01 M AgNo3
after mixing 10 drops 0.02 M K2Cr2O7, 1 mL gelatin solution, 10 drops 0.01 M AgNo3 what was the product
silver dichromate but no precipitate
reddish-brown precipitate
what is the role of gelatin in the experiment
protective colloid
brownian movement
random movement of microscopic particles suspended in a fluid due to particle collision
tyndall effect
scattering of light by colloidal particles; beam of light passes thru a colloidal solution
protective colloid
substance that stabilizes a colloidal dispersion by preventing the particles from aggregating or settling
