Lab.3. Colloidal solutions
REPORT
NAME…………………………………………..
FIRST NAME:…………………………………………….
STUDENT GROUP……………………………………..
DATE OF LABORATORY………………………………
Part.1.
Coagulation of iron hydroxide sol.
KCl as the coagulate agent.
Notice the number of tube where coagulation took place using asterisks (in
Table 1).
Table 1. Estimation of coagulation force of KCl
Number of tube
1
2
3
4
5
Volume of KCl (cm3)
1
3
5
7
9
9
7
5
3
1
10
10
10
10
10
Volume of water (cm3)
3
Volume of solution (cm )
Notices
On the base results from the first experiment estimate the force of KCl as coagulate agent.
The coagulative force is estimated from equation:
mk 
ac
 1000 ( mM L-1)
20
where:
mk – coagulate force, mM L-1
a – volume of electrolyte cause coagulation of 20 cm3 of sol, (use the volume of KCl from the
first tube in which the coagulation happened)
c – concentration of electrolyte M L-1.
A coagulation force of KCl is equal......................................
1
Lab.3. Colloidal solutions
K2SO4 as the coagulate agent.
This same procedure repeats with solution of K2SO4. The volume of added to the tubes are: 1,
2, 4, 6, 8 cm3 of (c = 0.001 M L-1). Notice the number of tube where coagulation took place
using asterisks in Table 2.
Table 2. Estimation of coagulation force of K2SO4.
Number of tube
1
2
3
4
5
Volume of K2SO4 (cm3)
1
3
5
7
9
Volume of water (cm3)
9
7
5
3
1
Volume of solution (cm3)
10
10
10
10
10
Notices
The coagulative force is estimated from equation:
mk 
ac
 1000 (mM L-1)
20
where:
mk – coagulate force, mM L-1
a – volume of electrolyte cause coagulation of 20 cm3 of sol, use the volume of K2SO4 from
the first tube in which the coagulation happened
c – concentration of electrolyte M L-1.
A coagulation force of K 2SO4 is equal......................................
Answer the questions:
1. What kind of ions causes coagulation process?
2. What is the coagulative force of investigated ions (the same or different for each ion)?
2
Lab.3. Colloidal solutions
PART II
Coagulation of a protein (the white of egg)
Table 3. Estimation of protein coagulation
Test tube
Coagulation effect
Positive effect
1.
KCl (1%)
2.
K2SO4 (1%)
3
CuCl2 (1%)
4.
CuSO4 (1%)
5.
Ethanol
Result after adding of the
ethanol
(denaturation)
Negative effect
Answer the question:
What kinds of solution cause coagulation of proteins?
3