Final answer:
To determine the change in vapor pressure when adding 180 grams of glycerin, Raoult's Law is used, requiring knowledge of the mole fractions of glycerin and water, and the vapor pressure of pure glycerin.
Step-by-step explanation:
To explain the change in vapor pressure when 180 grams of glycerin (glyeraldehyde) are added, we must use Raoult's law. Raoult's Law states that the partial vapor pressure of a component in a solution is equal to the mole fraction of the component times the vapor pressure of the pure component. To calculate the vapor pressure change, we would need the vapor pressure of pure glycerin and the initial vapor pressure of the solution. This information can then be used to find the mole fraction of glycerin and water, which are used to calculate the new vapor pressure of the solution.
The process involves several steps: calculating the number of moles of glycerin and water, determining their respective mole fractions, and then applying Raoult's law to find the final vapor pressure. It is important to remember that the addition of a non-volatile solute to a solvent will typically decrease the solution's vapor pressure compared to the pure solvent due to the solute particles occupying surface space in the solution and consequently, reducing the number of solvent molecules that can escape into the vapor phase.