The Change In Boiling Point For A Solution Is Always

Question: Colligative properties can be observed because the presence of solute particles obstructs:

Select the correct answer below:

physical processes

chemical processes

expansion

contraction

Answer: physical processes

Colligative properties are typically observed during things like phase changes, which are exclusively physical processes.

Question:

Answer: Their freezing points

The identity of the solvent

These solutions have the same concentration and therefore the same freezing point. The solvent is water in each. However, because density depends on the type of solute in a solution (and the solute is different in each), their densities are almost certainly not the same.

Question: Three aqueous solutions of different volumes are prepared. One is 3 M in glucose, one is 3 M in fructose, and one is 3 M in sucrose. Which of the following must these solutions have in common?

Answer:

Question: When a solution with a nonvolatile solute is prepared, which of the following will DEFINITELY decrease relative to the pure solvent? Select all that apply.

Select all that apply:

Freezing point of solution

Vapor pressure of solution

Boiling point of solution

All of the above

Answer: Freezing point of solution

Vapor pressure of solution

The vapor pressure and freezing point will be lower than that of the solvent when a nonvolatile solute is introduced, while the solution’s boiling point will be higher.

Question:

Answer:

Question: What is the mole fraction of potassium dichromate, K2Cr2O7, in a solution prepared from 24.42 g of potassium dichromate and 240. g of water? Report your answer in scientific notation with three significant figures.

Answer: $\text{X =}\ 6.19\times10^{-3}$X = 6.19×10−3​

To find the mole fraction we use:

mol K2Cr2O7=24.42 g K2Cr2O7×1 mol K2Cr2O7294.181 g=0.08301 mol K2Cr2O7mol H2O=240. g H2O×1 mol H2O18.015 g H2O=13.3 mol H2OXK2Cr2O7=mol K2Cr2O7total mol=0.08301 mol K2Cr2O713.4 total mol=6.19×10−3

Question: In order for a solute to decrease the vapor pressure of the solution, the solute must be:

Select the correct answer below:

ionic

covalent

volatile

nonvolatile

Answer:

Question: The partial pressure of a solution component will always be:

Select the correct answer below:

less than its vapor pressure in pure form

more than its vapor pressure in pure form

equal to its vapor pressure in pure form

depends on the substance

Answer: less than its vapor pressure in pure form

Because the vapor pressure in pure form is being multiplied by the mole fraction, and the mole fraction must always be between zero and one, we will always get a partial pressure that is some fraction of the vapor pressure in pure form.

Question: The boiling point elevation constant:

Answer:

Question: The change in boiling point for a solution does NOT depend on:

Select the correct answer below:

molecular mass of the solute

size of solute particles

chemical identity of the solute

all of the above

Answer: all of the above

None of these are parameters that affect the boiling point of a solution.