Q: A student mixes 50.0 mL of 1.00 M HCl with 50.0 mL of 1.00 M NaOH in a coffee-cup calorimeter. The temperature rises by 6.0°C. If the specific heat capacity of the solution is $$4.18 \ \mathrm{J} \cdot \mathrm{g}^{-1} \cdot \mathrm{K}^{-1}$$ and the density is $$1.00 \ \mathrm{g} \cdot \mathrm{mL}^{-1}$$, what is the heat evolved in the reaction?

$$q = 4.18 \times 100 \times 6.0 = 2508 \ \mathrm{J}$$

Q: A gas occupies 2.00 L at 1.00 atm and 300 K. What will be its volume at 2.00 atm and 300 K, assuming ideal behavior?

$$V_2$$ = $$V_1$$ \times \frac{$$P_1$$}{$$P_2$$} = 2.00 \times \frac{1.00}{2.00} = 1.00 \ \mathrm{L}$$

Q: A sample of gas is collected over water at 25°C. The total pressure is 760 mmHg, and the vapor pressure of water at 25°C is 24 mmHg. What is the partial pressure of the dry gas?

$$P_{\text{gas}} = 760 - 24 = 736 \ \mathrm{mmHg}$$

Question 1

Which of the following best describes the main focus of General Chemistry II (CH 222Z) at Oregon State University?

Accepted Answer

The exploration and application of stoichiometry, thermochemistry, kinetics, and equilibrium in the context of solids, liquids, gases, and solutions.

Question 2

A student mixes 50.0 mL of 1.00 M HCl with 50.0 mL of 1.00 M NaOH in a coffee-cup calorimeter. The temperature rises by 6.0°C. If the specific heat capacity of the solution is $$4.18 \ \mathrm{J} \cdot \mathrm{g}^{-1} \cdot \mathrm{K}^{-1}$$ and the density is $$1.00 \ \mathrm{g} \cdot \mathrm{mL}^{-1}$$, what is the heat evolved in the reaction?

Accepted Answer

$$q = 4.18 	imes 100 	imes 6.0 = 2508 \ \mathrm{J}$$

Question 3

Which of the following statements about intermolecular forces is correct?

Accepted Answer

Dipole-dipole interactions occur between polar molecules.

Question 4

A gas occupies 2.00 L at 1.00 atm and 300 K. What will be its volume at 2.00 atm and 300 K, assuming ideal behavior?

Accepted Answer

$$V_2$$ = $$V_1$$ 	imes \frac{$$P_1$$}{$$P_2$$} = 2.00 	imes \frac{1.00}{2.00} = 1.00 \ \mathrm{L}$$

Question 5

Which of the following best explains why salt (NaCl) is used to melt ice on roads in winter?

Accepted Answer

Salt decreases the freezing point of water, causing ice to melt at lower temperatures.

Question 6

Which equation correctly represents the relationship between the rate constant $$k$$ and temperature $$T$$ according to the Arrhenius equation?

Accepted Answer

$$k = A e$$^{-E_a/(RT)}$$

Question 7

A reaction is found to be first order in A and second order in B. Which of the following is the correct rate law for the reaction?

Accepted Answer

$$	ext{rate} = k[A][B]^2$$

Question 8

Which of the following statements about chemical equilibrium is correct?

Accepted Answer

At equilibrium, the rates of the forward and reverse reactions are equal.

Question 9

Which of the following is a colligative property of solutions?

Accepted Answer

Boiling point elevation

Question 10

A sample of gas is collected over water at 25°C. The total pressure is 760 mmHg, and the vapor pressure of water at 25°C is 24 mmHg. What is the partial pressure of the dry gas?

Accepted Answer

$$P_{	ext{gas}} = 760 - 24 = 736 \ \mathrm{mmHg}$$

Question 11

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

Accepted Answer

A catalyst decreases the activation energy, increasing the reaction rate.

Question 12

Which of the following is the correct expression for the equilibrium constant $$K_c$$ for the reaction $$aA + bB \rightleftharpoons cC + dD$$?

Accepted Answer

$$K_c = \frac{[C]^c[D]^d}{[A]^a[B]^b}$$

Question 13

Which of the following scenarios best illustrates the application of Le Chatelier’s Principle?

Accepted Answer

Increasing the pressure on a system at equilibrium shifts the position toward the side with fewer moles of gas.

Question 14

Which of the following is the correct formula for calculating the molality ($$m) of a $$solution?

Accepted Answer

$$m = \frac{	ext{moles of solute}}{	ext{kg of solvent}}$$

Question 15

A reaction has an enthalpy change $$\Delta H = -100 \ \mathrm{kJ}$$ and an entropy change $$\Delta S = -200 \ \mathrm{J} \cdot \mathrm{K}^{-1}. At $$what temperature (in K) does the reaction become non-spontaneous?

Accepted Answer

$$T = \frac{\Delta H}{\Delta S} = \frac{-100,000}{-200} = 500 \ \mathrm{K}$$

Question 16

Which of the following best describes why water has a relatively high boiling point compared to other group 16 hydrides?

Accepted Answer

Water molecules form strong hydrogen bonds with each other.

Question 17

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

Accepted Answer

$$\ln [A]_t = -kt + \ln [A]_0$$

Question 18

A solution is prepared by dissolving 10.0 g of NaCl in 100.0 g of water. What is the mass percent of NaCl in the solution?

Accepted Answer

$$	ext{Mass percent} = \frac{10.0}{10.0 + 100.0} 	imes 100\% = 9.09\%$$

Question 19

Which of the following best explains why increasing the temperature generally increases the rate of a chemical reaction?

Accepted Answer

Molecules move faster and collide more frequently with greater energy.

General Chemistry II (CH 222Z) Syllabus and Course Structure

Guida di studio - Domande di pratica

Study guide - Flashcard