What is the boiling point of a solution of 12.0 g of urea (CH₄N₂O)in 165.0 g of water? (K_b (H₂O)= 0.52 °C/m) A)99.4°C B)100.0 °C C)100.6°C D)106.2°C E)108.4°C

Question

Quizplus · Accepted Answer

We can use the formula:
ΔTb = Kb x molality
where ΔTb is the boiling point elevation, Kb is the boiling point elevation constant for water (0.52 °C/m), and molality is the concentration unit in mol solute per kg solvent.
First, we need to calculate the molality of the solution:
moles of urea = mass/molar mass = 12.0 g/60.06 g/mol = 0.1997 mol
mass of water = 165.0 g
molality = moles of solute/kg of solvent = 0.1997 mol/0.165 kg = 1.211 mol/kg
Then, we can calculate the boiling point elevation:
ΔTb = 0.52 °C/m x 1.211 mol/kg = 0.6309 °C
The boiling point of the solution is then:
boiling point = normal boiling point of water + ΔTb = 100.0°C + 0.6309°C = 100.6°C
Therefore, the correct answer is C.

What Is the Boiling Point of a Solution of 12