Q: A solution is prepared by dissolving 10.0 g of NaCl (molar mass = 58.44 g/mol) in 100.0 g of water. What is the molality ($$m) of $$the solution?

$$m = \frac{10.0}{58.44} \div 0.100 = 1.71\ \text{mol/kg}$$

Q: A student prepares a solution by dissolving 5.00 g of glucose (C$$_6H$_{12}O$_6$$, molar mass = 180.16 g/mol) in enough water to make 250.0 mL of solution. What is the molarity ($$M) of $$the solution?

$$M = \frac{5.00}{180.16} \div 0.250 = 0.111\ \text{M}$$

Q: Given the following data for a reaction: $$[A]_0 = 0.50\ \text{M}$$, $$[A]_t = 0.25\ \text{M}$$ after 10 min, and the reaction is first order. What is the rate constant $$k$$?

$$k = \frac{\ln(0.50/0.25)}{10} = 0.0693\ \text{min}^{-1}$$

Question 1

Which of the following molecules exhibits hydrogen bonding as its strongest intermolecular force?

Accepted Answer

NH\_3

Question 2

A solution is prepared by dissolving 10.0 g of NaCl (molar mass = 58.44 g/mol) in 100.0 g of water. What is the molality ($$m) of $$the solution?

Accepted Answer

$$m = \frac{10.0}{58.44} \div 0.100 = 1.71\ 	ext{mol/kg}$$

Question 3

Which of the following statements best describes the effect of increasing temperature on the solubility of a gas in water?

Accepted Answer

The solubility decreases because gas molecules escape more easily.

Question 4

Which of the following is a colligative property?

Accepted Answer

Boiling-point elevation

Question 5

A reaction has a rate law: $$	ext{rate} = k[NO_2$]^2. If $$the concentration of $$NO_2 is $$doubled, how does the rate change?

Accepted Answer

The rate increases by a factor of four.

Question 6

Which of the following best explains why ionic compounds generally have higher melting points than molecular compounds?

Accepted Answer

Ionic bonds are stronger than intermolecular forces.

Question 7

What is the van’t Hoff factor ($$i) $$for a solution of $$CaCl_2$$ assuming complete dissociation?

Accepted Answer

$$i = 3$$

Question 8

Which of the following best describes a saturated solution?

Accepted Answer

A solution in which no more solute can dissolve at a given temperature.

Question 9

A student prepares a solution by dissolving 5.00 g of glucose (C$$_6H$_{12}O$_6$$, molar mass = 180.16 g/mol) in enough water to make 250.0 mL of solution. What is the molarity ($$M) of $$the solution?

Accepted Answer

$$M = \frac{5.00}{180.16} \div 0.250 = 0.111\ 	ext{M}$$

Question 10

Which of the following is true about the entropy change when NaCl dissolves in water?

Accepted Answer

Entropy increases because the ions become more disordered.

Question 11

Which of the following best describes the effect of a catalyst on a chemical reaction?

Accepted Answer

It lowers the activation energy, increasing the reaction rate.

Question 12

Given the following data for a reaction: $$[A]_0 = 0.50\ 	ext{M}$$, $$[A]_t = 0.25\ 	ext{M}$$ after 10 min, and the reaction is first order. What is the rate constant $$k$$?

Accepted Answer

$$k = \frac{\ln(0.50/0.25)}{10} = 0.0693\ 	ext{min}^{-1}$$

Question 13

Which of the following pairs is most likely to be miscible?

Accepted Answer

Water and ethanol

Question 14

A solution contains 0.10 mol of NaCl and 0.90 mol of water. What is the mole fraction ($$\chi) of $$NaCl?

Accepted Answer

$$\chi = \frac{0.10}{0.10 + 0.90} = 0.10$$

Question 15

Which of the following best describes the relationship between intermolecular forces and boiling point?

Accepted Answer

Stronger intermolecular forces lead to higher boiling points.

Question 16

A reaction has an activation energy ($$E_a) of 50 kJ/$$mol. If the temperature increases, what happens to the rate constant $$k$$?

Accepted Answer

$$k$$ increases

Question 17

Which of the following is the correct expression for the rate of disappearance of $$A in $$the reaction $$2A \rightarrow B$$?

Accepted Answer

$$	ext{rate} = -\frac{1}{2} \frac{d[A]}{dt}$$

Question 18

Which of the following is the best definition of a colligative property?

Accepted Answer

A property that depends only on the number of solute particles, not their identity.

Question 19

Which of the following is the correct integrated rate law for a second-order reaction?

Accepted Answer

$$\frac{1}{[A]} = kt + \frac{1}{[A]_0}$$

General Chemistry: Study Guide for Exam 1 (Chapters 11, 13, 14)

Guida di studio - Domande di pratica

Study guide - Flashcard