Practicing Success
The elevation in boiling point for 13.44 g of CuCl2 dissolved in 1 kg of water as solvent will be (Kb = 0.52 kg/J, molar mass of CuCl2 = 134.4 g/mol) |
0.05 0.10 0.16 0.20 |
0.16 |
To calculate the elevation in boiling point caused by the addition of CuCl2 to water, we can use the formula: \(\Delta T_b = K_b \cdot m \cdot i\) where: First, we need to calculate the molality of CuCl2. Molality (\(m\)) is defined as the moles of solute per kilogram of solvent. Since we have 13.44 g of CuCl2 and 1 kg of water, we need to convert the mass of CuCl2 to moles: \(\text{moles of }CuCl_2 = \frac{{\text{mass of }CuCl_2}}{{\text{molar mass of }CuCl_2}}\) Now we can calculate the molality: \(m = \frac{{\text{moles of solute}}}{{\text{mass of solvent kg}}} = \frac{{0.1 \, \text{mol}}}{{1 \, \text{kg}}} = 0.1 \, \text{mol/kg}\) The Van't Hoff factor (\(i\)) for CuCl2 is 3 because it dissociates into three particles (Cu2+ and 2 Cl-) when it dissolves. Now we can calculate the elevation in boiling point: \(\Delta T_b = K_b \cdot m \cdot i = 0.52 \, \text{kg/J} \cdot 0.1 \, \text{mol/kg} \cdot 3 = 0.156 \, \text{K}\) The elevation in boiling point is 0.156 K, which is approximately equal to 0.16 K. Therefore, the answer is option (3). |