Final answer:
The lab question focuses on the calculation of vapor pressure of a urea-water solution, where Raoult's Law is used after determining the molar concentration of urea. 5.00 g of urea is dissolved in 0.100 kg of water and the decrease in vapor pressure is proportionate to the mole fraction of water in the solution.
Step-by-step explanation:
The subject in question pertains to the preparation of a urea solution and the determination of its vapor pressure. To answer the Check Your Learning question, one must first calculate the molar concentration of urea, CO(NH₂)₂, in the solution, which involves dissolving a measured amount of urea in a given quantity of water. According to the information given, we have 5.00 g of urea and 0.100 kg of water.
To determine the vapor pressure of the resulting solution, one must apply Raoult's Law, which states that the vapor pressure of a solution is directly proportional to the mole fraction of the solvent.
Presuming ideal behavior, the change in vapor pressure is proportional to the amount of nonvolatile solute (urea in this case) present in the solution.
First, we need to calculate the moles of urea using its molar mass (60.06 g/mol). Then we'll find the mole fraction of water by dividing the moles of water by the total moles of both urea and water.
Since urea does not contribute to the vapor pressure, we'll only consider the mole fraction of water in the solution when we multiply by the vapor pressure of pure water to find the final vapor pressure of the solution.