Calculate the number of moles of nonvolatile solute dissolved in 0.5 kg solvent if molal elevation constant for solvent is 2 ~kg ~K ~mol ⁻¹ [ T _ b =0.8 ~K ]

Step-by-step solution

The number of moles is determined using the boiling point elevation formula T_b = K_b m , with T_b = 0.8 K and K_b = 2 kg K mol ⁻¹ . Molality m relates to moles n and solvent mass 0.5 kg as m = n / 0.5 . Substituting into the elevation formula: 0.8 = 2 n 0.5 Solving for n : n = 0.8 0.5 2 = 0.4 2 = 0.2 mol The number of moles of nonvolatile solute is 0.2 .