Colloids and Their Properties

Question 1

title of experiment 3

Answer 1

Colloids and Their Properties

Question 2

two phases of colloids

Answer 2

continuous phase (dispersion medium)
discontinuous phases (dispersed phase_

Question 3

Contains particles larger than the solute particles of a true solution; homogenous to the naked eye

Answer 3

colloidal system

Question 4

examination of a colloid under the microscope will show particle movement called

Answer 4

Brownian Movement

Question 5

When subjected to a beam of light in a darkened room, colloids show

Answer 5

Tyndall effect

Question 6

example of liquid colloidal system

Answer 6

milk

Question 7

protein in milk

Answer 7

casein

Question 8

casein contains

Answer 8

negative charges on the particle surface which prevents particles from coalescing

Question 9

what will happen if acetic acid is added to milk

Answer 9

the H+ released by acetic acid neutralizes the negative charges on the particle surface, causing curd formation

Question 10

different properties of colloids help in understanding

Answer 10

• proteins
• foods
• medicines
• enzymes
• fats

Question 11

Colloid play an important role in

Answer 11

• digestion
• metabolism
• most all phase of physiological processes

Question 12

materials/reagents needed for the formation of curd

Answer 12

1. 0.1 M CuSO4
2. 10% skim milk mixture
3. 3 M HAc

Question 13

Test Tubes and their contents

Answer 13

1 - 4 mL 0.1 CuSO4
2 - 4 mL 10 % skim milk mixture
3. - 4 mL skim milk 3 M HAc

Question 14

what tube is there an evidence of curd formation?

Answer 14

3 - skim milk and 3 M HAc

Question 15

which particles are large enough to be retained by filter paper?

Answer 15

particles of skim milk and 3 M HAc mixture

Question 16

You filtered each contents of tubes 1 and 2, did the dialysis set up, what happened?

Answer 16

• blue color outside the dialysis bag of CuSO4 filtrate indicates copper ions
• there’s turbidity outside the dialysis bag of skim milk

Question 17

formation of protective colloids reagents (1)

Answer 17

10 drops 0.2 M K2Cr207
4 mL distilled water
10 drops 0.04 M AgNo3

Question 18

after mixing 10 drops 0.2 K2Cr207 , 4 mL distilled water , 10 drops 0.04 AgNo3 what was the product

Answer 18

silver dichromate (there’s a precipitate)

Question 19

formation of protective colloids reagents (another test tube)

Answer 19

10 drops 0.02 M K2Cr2O7, 1 mL gelatin solution, 10 drops 0.01 M AgNo3

Question 20

after mixing 10 drops 0.02 M K2Cr2O7, 1 mL gelatin solution, 10 drops 0.01 M AgNo3 what was the product

Answer 20

silver dichromate but no precipitate
reddish-brown precipitate

Question 21

what is the role of gelatin in the experiment

Answer 21

protective colloid

Question 22

brownian movement

Answer 22

random movement of microscopic particles suspended in a fluid due to particle collision

Question 24

tyndall effect

Answer 24

scattering of light by colloidal particles; beam of light passes thru a colloidal solution

Question 25

protective colloid

Answer 25

substance that stabilizes a colloidal dispersion by preventing the particles from aggregating or settling