Question

Find the osmotic pressure of $\dfrac{M{10}$ urea solution at $27^\circ\mathrm{C}$ \ (Given: $R=0.0821$ L\,atm\,K$^{-1}$\,mol$^{-1}$).}

Hint:

Use \(\pi = iMRT\) and remember to convert temperature to Kelvin. For non-electrolytes, \(i=1\); for electrolytes, include \(i\) (van't Hoff factor).

Answer 1

For a non–electrolyte (urea), osmotic pressure is given by \(\pi = iMRT\) with \(i=1\).
Given \(M = \dfrac{M}{10} = 0.10\ \text{mol L}^{-1}\), \(T = 27^\circ\mathrm{C} = 300\ \text{K}\).
\[ \pi = (1)\times 0.10 \times 0.0821 \times 300 = 2.463\ \text{atm} \]
\[ \boxed{\pi \approx 2.46\ \text{atm}} \]