Question 1

Which of the following best describes the process of osmosis as shown in the first image?

Accepted Answer

The flow of solvent from a region of low solute concentration to a region of high solute concentration through a semipermeable membrane.

Question 2

What is the primary function of a semipermeable membrane in osmosis?

Accepted Answer

It only allows solvent to pass through, not solute.

Question 3

Which equation correctly represents the relationship for osmotic pressure ($$\Pi) of a $$solution?

Accepted Answer

$$\Pi = iMRT$$

Question 4

A 0.50 M solution of $$\mathrm{$$MgCl_2$$} is $$prepared. What is the theoretical van’t Hoff factor ($$i) $$for this solution?

Accepted Answer

3

Question 5

Why is the measured van’t Hoff factor for $$\mathrm{NaCl} in $$water typically less than the theoretical value?

Accepted Answer

Because of ion pairing in solution, which reduces the number of free particles.

Question 6

Which of the following solutions will have the highest boiling point elevation, assuming complete dissociation?

Accepted Answer

0.50 M $$\mathrm{$$MgCl_2$$}$$

Question 7

What is the main reason soaps are effective at cleaning oily substances?

Accepted Answer

They have both hydrophilic and hydrophobic regions, allowing them to form micelles that trap oils.

Question 8

What structure do soap molecules form in water to help emulsify oils?

Accepted Answer

Micelles

Question 9

In the context of chemical kinetics, what does the slope of the tangent to a concentration vs. time curve at a specific point represent?

Accepted Answer

The instantaneous rate of the reaction at that specific time.

Question 10

For the reaction $$2\mathrm{H_2$}(g) + \mathrm{O_2$}(g) \rightarrow 2\mathrm{H_2O}(g)$$, if the rate of disappearance of $$\mathrm{H_2$} is$$ $$0.10\ \mathrm{M/s}$$, what is the rate of disappearance of $$\mathrm{O_2$}$$?

Accepted Answer

$$0.05\ \mathrm{M/s}$$

Question 11

Given the reaction $$\mathrm{A} + 2\mathrm{B} \rightarrow \mathrm{C}$$, if the initial rate of formation of C is $$0.100\ \mathrm{M/s}$$, what is $$\frac{d[\mathrm{B}]}{dt} at $$the same time?

Accepted Answer

$$-0.200\ \mathrm{M/s}$$

Question 12

Why does the rate of a chemical reaction generally decrease over time?

Accepted Answer

Because the concentration of reactants decreases.

Question 13

Which of the following best explains why the boiling point elevation of a $$0.50\ \mathrm{M}$$ $$\mathrm{$$MgCl_2$$}$$ solution is higher than that of a $$0.50\ \mathrm{M}$$ $$\mathrm{NaCl}$$ solution?

Accepted Answer

$$\mathrm{$$MgCl_2$$}$$ produces more ions per formula unit in solution.

Question 14

A soap molecule has a hydrophilic head and a hydrophobic tail. What is the role of the hydrophobic tail in cleaning?

Accepted Answer

It binds to oil and grease, allowing them to be surrounded by the soap micelle.

Question 15

Which of the following statements about the rate of a reaction is correct?

Accepted Answer

The rate of a reaction is measured by the change in concentration of a reactant or product per unit time.

Question 16

If a solution of $$\mathrm{$$FeCl_3$$}$$ has a measured van’t Hoff factor of 3.4 at a certain concentration, what does this indicate?

Accepted Answer

Some ion pairing occurs, so fewer than four particles per formula unit are present.

Question 17

Which of the following best describes the function of micelles in soap solutions?

Accepted Answer

They trap nonpolar substances in their hydrophobic core, allowing them to be washed away with water.

Question 18

In a reaction $$aA + bB \rightarrow cC + dD$$, how is the rate of disappearance of A related to the rate of appearance of C?

Accepted Answer

$$\frac{1}{a}\frac{d[A]}{dt} = \frac{1}{c}\frac{d[C]}{dt}$$

Colligative Properties, Soaps, and Chemical Kinetics: Study Notes for General Chemistry

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