Calculation

a) 50ml of suspensions containing 5% w/v of sulpharmerazine which containing 10-2, 5 x 10-3, 10-3, 5 x 10-4, 10-4, 5x 10-5, and 10-5 molar concentrations of Calcium Chloride. ( 10-2 are provided ).

By using this formula, we can get the amount of calcium chloride to be added in making 50 ml suspensions containing 5% w/v of sulpharmerazine.

M1V1 = M2V2

M2 = 5 x 10-3, 10-3, 5 x 10-4, 10-4, 5x 10-5, and 10-5 M , V2 = 50ml

M1 = 0.01M

Thus,

V1 = ( M2 . V2 ) / M1

For,

i) 5 x 10-3 molar concentrations, iv) 10-4 molar concentrations,

V2 = ( 5 x 10-3 x 50 ) / (0.01) V2 = ( 5 x 10-3 x 50 ) / (0.01) = 25ml = 0.5ml

ii) 10-3 molar concentrations v) 5x 10-5 molar concentration

V2 = ( 10-3 x 50 ) / (0.01) V2 = ( 5 x 10-5 x 50 ) / (0.01) = 5ml = 0.25ml

iii) 5 x 10-4 molar concentrations vi) 10-5 molar concentration V2 = ( 5 x 10-4 x 50 ) / (0.01) V2 = ( 10-5 x 50 ) / (0.01) = 2.5ml = 0.05

Weight of calcium chloride used,

= 5/100 (w/v) from 50ml

= 2.5gram

Measuring Cylinder

Original height,

H0 (cm)

Ultimate settled height, Hu (cm)

Sedimentation volume ratio,F

( Hu / H0 ), cm

Percentage sedimentation volume ratio (%)

15 min

30 min

60 min

1 week

A (5 x 10-3)

9.70

0.70

0.80

0.85

0.60

0.06

6

B (10-3 )

9.60

0.10

0.15

0.15

0.10

0.01

1

C (5 x 10-4)

10.0

0.25

0.30

0.35

0.35

0.04

4

D (10-4 )

9.80

0.90

0.90

0.90

0.80

0.08

8

E (5x 10-5)

10.00

0.95

1.00

1.00

1.00

0.10

10

F (10-5 )

9.60

0.95

0.95

1.00

1.00

0.10

10

Table 1

Sedimentation volume ratio (F) can be calculated as follow,

F = Hu / H0

F = Sedimentation volume ratio

Hu = Ultimate settled height / Final height of sediment

H0 = Original height of the suspension settle

Percentage sedimentation volume ratio can be calculated as follow,

F = (Hu / H0) x 100

Discussion

Based on the previous experiment, we had conducted an experiment to make 50ml of suspensions that contain 5% w/v of sulpharmerazine with various concentration of 0.01M Calcium Chloride in seven different measuring cylinder. The molar concentration of the electrolyte started with 10-2 then followed by 5x10-3 , 10-3, 5x10—4, 10-4, 5x10-5 and 10-5.

All the suspensions leaved for 15minutes, 30 minutes, 60 minutes and 1 week. The rate of sedimentation was recorded.. The three first suspension A,B and C showed the rate of sedimentation by 6%,1% and 4% respectively and the rest about 10%. This might be because of the addition of inorganic electrolyte to an aqueous suspension will alter the zeta potential of the dispersed particles. The flocculation occurred if the zeta value is lowered sufficiently.

The addition of small quantities of calcium chloride made it possible for flocculation to occur below those needed in the absence of salt. The concentration chosen will be that which produced the desired degree of flocculation. If too much or excessive addition of electrolyte or charge reversal may occur on each particle, and will forming once again a deflocculated system.

CONCLUSION:

Concentration of electrolyte that is calcium chloride affected the stability of a suspension of sulphamerazine. As the electrolyte concentration decreased, the percentage sedimentation volume ratio also will increase. For this experiment, we have used different concentration of calcium chloride which are 5x10-3, 10-3, 5x10-4, 10-4, 5x10-5 and 10-5 molar concentration of calcium chloride. Based on the DLVO theory, in high concentration of electrolyte, there is some force between charged surfaces interacting through a suspension medium. The higher the concentration of calcium chloride, the stronger the force between the charged surfaces interacting in the suspension. Hence, the percentage of sedimentation will become lower. Based on our experiment, the higher concentration of calcium chloride that is 5x10-3 has high percentage of sedimentation compare to 10-3, 5x10-4 and 10-4. There may occur some error when we doing the dilution of the calcium chloride. The percentage of sedimentation of suspension containing 5x10-3 molar concentration of calcium chloride should be the lowest among others concentration. The other suspension containing different concentration of calcium chloride follows the DLVO theory. Precaution that we should take is when we doing the dilution and we should also label the measuring cylinder correctly when doing this experiment.