Question

Can I please get some Chemistry help?

Answer 1

As a nonvolatile solid is added to a solvent, in what way are the properties of the solvent changed?
Group of answer choices

The vapor pressure is increased and the boiling point is increased

The vapor pressure is lowered and the boiling point is increased

The vapor pressure is lowered and the boiling point is lowered

The vapor pressure is lowered and the freezing point is increased

Answer 2

@Katrin369

Answer 3

@AZ

Answer 4

Ok, try this.

The addition of a nonvolatile solute results in a lowering of the vapor pressure of the solvent. The solution on the right left has had some of its solvent particles replaced by solute particles. Since the solute particles do not evaporate, the vapor pressure of the solution is lower than that of the pure solvent.

Answer 5

I understand that the vapor pressure lowers, but I wonder what happens to the boiling/freezing points.

Answer 6

The effect of adding a solute to a solvent has the opposite effect on the freezing point of a solution as it does on the boiling point. A solution will have a lower freezing point than a pure solvent. The freezing point is the temperature at which the liquid changes to a solid.

Answer 7

Vapor pressure, boiling point, freezing point are all colligative properties- which means that the effects are dependent not on what type of solute is added but the NUMBER of solute particles dissolved in the solution

I'm not sure if you've heard the phrase "boiling point elevation" and "freezing point depression"
These tell us what happens when you add more solute to a solution in addition to the vapor pressure being lowered

Answer 8

So as the vapor pressure is being lowered the boiling point is increasing

Answer 9

That is correct and the freezing point is decreasing

Answer 10

Let me try to find a source that could perhaps explain the phenomenon (bc as you progress further in these courses, you kind of tend to keep the key takeaways and lose sight of the actual reasons haha)

Answer 11

Okay thank you. If you could, send it to my messages

Answer 12

`The Relationship Between Boiling Point Elevation and Vapor Pressure`

`Boiling point elevation can be explained in terms of vapor pressure. Vapor pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature. In layman’s terms, it is simply a measure of the tendency of the solution molecules to escape by entering the gas phase. A liquid boils when its vapor pressure is equal to the air pressure.`


`Boiling Point Elevation`

`A solvent’s vapor pressure will lower when a solute is added. This happens because of the displacement of solvent molecules by the solute. This means that some of the of solvent molecules at the surface of the liquid are replaced by the solute; it can occur in both electrolytic and non-electrolytic solutions. The lower number of solvent molecules at the surface means that fewer will evaporate, and thus the vapor pressure is lowered. For the vapor pressure to equal the atmospheric pressure, a higher temperature is required, and a higher boiling point is observed.`

From: https://courses.lumenlearning.com/boundless-chemistry/chapter/colligative-properties-of-nonelectrolyte-solutions/

Answer 13

It explains it pretty nicely as to the reason why vapor pressure would decrease and as a result boiling point would elevate