Question

Intravenous, or IV, solutions used in medicine must exert the same osmotic pressure as blood to prevent a net flow of water into or out of the blood cells. The proper concentration for an intravenous NaCl solution is 0.90 g NaCl per 100. mL of solution (sometimes referred to as 0.90% m/v). If the van't Hoff factor of NaCl is ????=1.8, what is the osmotic pressure of blood at body temperature, 37 ∘C?

Answer 1

Answer:

$\boxed{\text{7.5 bar}}$

Explanation:

1. Find the molar concentration

Assume that we have 100 mL solution.

Mass of NaCl = 0.90 g

$\text{Moles of NaCl} = \text{0.90 g} \times \dfrac{\text{1 mol}}{\text{58.44 g}} = 0.0154 \text{ mol}\\\\c = \dfrac{\text{Moles of NaCl}}{\text{Litres of solution}} = \dfrac{0.0154 \text{ mol}}{\text{0.100 L}} = \text{0.154 mol/L}$

2. Find the osmotic pressure

The formula for osmotic pressure (Π) is

Π = icRT

T = (37 + 273.15) K = 310.15 K

$\Pi = 1.88 \times \text{0.154 mol}\cdot \text{L}^{-1} \times \text{0.083 14 bar}\cdot\text{L}\cdot\text{K}^{-1}\text{mol}^{-1} \times \text{310.15 K} = \text{7.5 bar}\\\\\text{The osmotic pressure of blood at body temperature is }\boxed{\textbf{7.5 bar}}$