The osmotic pressure of 9.69 * 10-3 M solutions of CaCl2 and urea at 25°C are 0.585 and 0.237 atm, respectively. Calculate the van't Hoff factor for the CaCl2 solution.

The van't Hoff factor is 2.55

Explanation:

Step 1: Data given

Osmotic pressure of CaCl2 = 0.585 atm

Osmotic pressure of urea = 0.237 atm

Concentration = 9.69 * 10^-3 M

Temperature = 25.0 °C

Step 2:

Π = iMRT

⇒ with Π = the osmotic pressure of CaCl2 = 0.585 atm

⇒ with i is the van't Hoff factor

⇒ with M = the molar concentration = 9.69 * 10^-3 M

⇒ with R = the gas constant = 0.0821 L*atm/mol*K

⇒ with T = the temperature = 25.0 °C = 298 K

0.605 atm = i (9.69 * 10^-3 M) (0.0821 L*atm/mol*K) (298K)

i = 2.55

The van't Hoff factor is 2.55