To compute for solidification time, three essential parameters are needed and these parameters are Chvorinov’s Constant (C), Volume (V) and Surface Area (A).
The formula for calculating solidification time:
t = C(V / A)
Where:
t = Solidification Time
C = Chvorinov’s Constant
V = Volume
A = Surface Area
Let’s solve an example;
Find the solidification time when the chvorinov’s constant is 15, the volume is 12 and the surface area is 8.
This implies that;
C = Chvorinov’s Constant = 15
V = Volume = 12
A = Surface Area = 8
t = C(V / A)
t = 15(12 / 8)
t = 15(1.5)
t = 22.5
Therefore, the solidification time is 22.5s.
Calculating the Chvorinov’s Constant when the Solidification Time, the Volume and the Surface Area is Given.
C = tA / V
Where:
C = Chvorinov’s Constant
t = Solidification Time
V = Volume
A = Surface Area
Let’s solve an example;
Find the Chvorinov’s Constant when the solidification time is 20, the volume is 12 and the surface area is 8.
This implies that;
t = Solidification Time = 20
V = Volume = 12
A = Surface Area = 8
To compute for the osmotic pressure, five parameters are needed and these parameters are Ideal Gas Constant (R), Temperature in Kelvin (T), Number of Moles (n), Volume (V) and Van’t Hoff’s Factor (i).
The formula for calculating osmotic pressure:
π = i nRT ⁄ V
Where;
π = osmotic pressure
n = number of moles
R = ideal gas constant
T = temperature in Kelvin
i = Van’t Hoff’s Factor
V = Volume
Let’s solve an example;
Find the osmotic pressure when the ideal gas constant is 0.08206 with a temperature in kelvin of 120, number of moles is 32, a volume of 48 and a van’t hoff’s factor of 24.
This implies that;
n = number of moles = 32
R = ideal gas constant = 0.08206
T = temperature in Kelvin = 120
i = Van’t Hoff’s Factor = 24
V = Volume = 48
π = i nRT ⁄ V
π = 24 32 x 0.08206 x 120 ⁄ 48
π = (24) (315.110) ⁄ (48)
π = (24)(6.5647)
π = 157.5
Therefore, the osmotic pressure is 157.5 atm.
Calculating the Van’t Hoff’s Factor using the Osmotic Pressure, Number of Moles, Temperature in Kelvin, Ideal Gas Constant and Volume.
i = Vπ / nRT
Where;
i = Van’t Hoff’s Factor
π = osmotic pressure
V = Volume
n = number of moles
R = ideal gas constant
T = temperature in Kelvin
Let’s solve an example;
Find the Van’t Hoff’s Factor when the osmotic pressure is 220, volume of 50, temperature in kelvin of 180 and number of moles of 60. (R = 0.08206)
This implies that;
π = osmotic pressure = 220
V = Volume = 50
n = number of moles = 60
R = ideal gas constant = 0.08206
T = temperature in Kelvin = 180
i = Vπ / nRT
i = 50 x 220 / 60 x 0.08206 x 180
i = 11000 / 866.808
i = 12.69
Therefore, the Van’t Hoff’s Factor is 12.69.
Calculating the Volume using the Osmotic Pressure, Number of Moles, Temperature in Kelvin, Ideal Gas Constant and Van’t Hoff’s Factor.
V = i (nRT) / π
Where;
V = Volume
i = Van’t Hoff’s Factor
π = osmotic pressure
n = number of moles
R = ideal gas constant
T = temperature in Kelvin
Let’s solve an example;
Find the volume when the osmotic pressure is 280, Van’t Hoff’s Factor of 40, temperature in kelvin of 90 and number of moles of 70. (R = 0.08206)
This implies that;
i = Van’t Hoff’s Factor = 40
π = osmotic pressure = 280
n = number of moles = 70
R = ideal gas constant = 0.08206
T = temperature in Kelvin = 90
V = i (nRT) / π
V = 40 (70 x 0.08206 x 90) / 280
V = 40 (516.978) / 280
V = 20679.12 / 280
V = 73.854
