Question

What is the osmotic pressure of a solution prepared from 13.7 g of the electrolyte HCl and enough water to make 0.500 L of solution at 18°C? [R = 0.08206 L • atm/K • mol]

Answer 1

Answer:

P = 17.9618 atm

Explanation:

The osmotic pressure can be calculated and treated as if we are talking about an ideal gas, and it's expression is the same:

pV = nRT

However the difference, is that instead of using moles, it use concentration so:

p = nRT/V ----> but M = n/V so

p = MRT

We have the temperature of 18 °C (K = 18+273.15 = 291.15 K) the value of R = 0.08206 L atm / K mol, so we need to calculate the concentration, and we have the mass of HCl, so we use the molar mass of HCl which is 36.45 g/mol:

n = 13.7/36.45 = 0.3759 moles

M = 0.3759/0.5 = 0.7518 M

Now that we have the concentration, let's solve for the osmotic pressure:

p = 0.7518 * 0.08206 * 291.15

p = 17.9618 atm