Q: A sample of air contains oxygen, nitrogen, and carbon dioxide gases. If the total pressure is 1.00 atm and the partial pressures of oxygen and nitrogen are 0.21 atm and 0.78 atm respectively, what is the partial pressure of carbon dioxide?

$$P_{CO_2$} = 1.00\ \text{atm} - (0.21\ \text{atm} + 0.78\ \text{atm}) = 0.01\ \text{atm}$$

Q: A 2.0 L container holds 0.5 mol of an ideal gas at 300 K. What is the pressure inside the container? (Use $$R = 0.0821\ \text{L}\cdot\text{atm}/\text{mol}\cdot\text{K})$$

$$P = \frac{nRT}{V} = \frac{0.5 \times 0.0821 \times 300}{2.0} = 6.16\ \text{atm}$$

Q: A solution is prepared by dissolving 10.0 g of NaCl in 90.0 g of water. What is the percent by mass of NaCl in the solution?

$$\text{Percent by mass} = \frac{10.0}{10.0 + 90.0} \times 100\% = 10\%$$

Q: A solution has $$[H^+] = 1.0 \times 10$$^{-4}$$\ \text{M}. $$What is its pH?

$$\text{pH} = -\log(1.0 \times 10$$^{-4}$$) = 4$$

Q: If the $$K_b of$$ $$NH_3 is$$ $$1.8 \times 10$$^{-5}$$, what is the K_a$ of its conjugate acid NH_4$^+$$? ($$K_w = 1.0 \times 10$$^{-14}$$)

$$K_a = \frac{K_w}{K_b} = \frac{1.0 \times 10$$^{-14}$$}{1.8 \times 10$$^{-5}$$} = 5.6 \times 10$$^{-10}$$

Question 1

A sample of air contains oxygen, nitrogen, and carbon dioxide gases. If the total pressure is 1.00 atm and the partial pressures of oxygen and nitrogen are 0.21 atm and 0.78 atm respectively, what is the partial pressure of carbon dioxide?

Accepted Answer

$$P_{CO_2$} = 1.00\ 	ext{atm} - (0.21\ 	ext{atm} + 0.78\ 	ext{atm}) = 0.01\ 	ext{atm}$$

Question 2

Which intermolecular force is primarily responsible for the meniscus observed in water in a glass cylinder?

Accepted Answer

Hydrogen bonding

Question 3

A 2.0 L container holds 0.5 mol of an ideal gas at 300 K. What is the pressure inside the container? (Use $$R = 0.0821\ 	ext{L}\cdot	ext{atm}/	ext{mol}\cdot	ext{K})$$

Accepted Answer

$$P = \frac{nRT}{V} = \frac{0.5 	imes 0.0821 	imes 300}{2.0} = 6.16\ 	ext{atm}$$

Question 4

Which statement best describes the behavior of real gases compared to ideal gases at high pressures?

Accepted Answer

Real gases deviate from ideal behavior due to increased intermolecular forces and finite molecular volume.

Question 5

A solution is prepared by dissolving 10.0 g of NaCl in 90.0 g of water. What is the percent by mass of NaCl in the solution?

Accepted Answer

$$	ext{Percent by mass} = \frac{10.0}{10.0 + 90.0} 	imes 100\% = 10\%$$

Question 6

Which of the following will increase the rate of a chemical reaction according to the collision theory?

Accepted Answer

Increasing the temperature

Question 7

Given the reaction: $$2NO_2 ightarrow 2NO + O_2$, the rate law is found to be $$	ext{Rate} = k[$$NO_2$$]^2$$. If the concentration of NO_2$ is doubled, what happens to the rate?

Accepted Answer

The rate increases by a factor of 4.

Question 8

For the equilibrium reaction $$N_2(g) + 3H_2(g$$) \rightleftharpoons 2NH_3(g)$$, what will happen if the pressure is increased?

Accepted Answer

The equilibrium will shift toward the side with fewer moles of gas, producing more $$NH_3.$$

Question 9

Which of the following is an amphiprotic substance?

Accepted Answer

$$HCO_3$$^-$$

Question 10

A solution has $$[H^+] = 1.0 	imes 10$$^{-4}$$\ 	ext{M}. $$What is its pH?

Accepted Answer

$$	ext{pH} = -\log(1.0 	imes 10$$^{-4}$$) = 4$$

Question 11

Which of the following is a strong acid?

Accepted Answer

HCl

Question 12

Given the base $$NH_3$$ and its conjugate acid $$NH_4$$^+$$, which statement is correct?

Accepted Answer

$$NH_4$$^+$$ is the conjugate acid of NH_3$.

Question 13

If the $$K_b of$$ $$NH_3 is$$ $$1.8 	imes 10$$^{-5}$$, what is the K_a$ of its conjugate acid NH_4$^+$$? ($$K_w = 1.0 	imes 10$$^{-14}$$)

Accepted Answer

$$K_a = \frac{K_w}{K_b} = \frac{1.0 	imes 10$$^{-14}$$}{1.8 	imes 10$$^{-5}$$} = 5.6 	imes 10$$^{-10}$$

Question 14

Which of the following best describes a voltaic cell?

Accepted Answer

A cell in which a spontaneous redox reaction generates electrical energy.

Question 15

In the reaction $$Zn(s) + Cu$$^{2+}$$(aq) \rightarrow Zn$$^{2+}$$(aq) + Cu(s)$$, which species is the reducing agent?

Accepted Answer

$$Zn(s)$$

Question 16

A reaction pathway graph shows a high peak between reactants and products. What does this peak represent?

Accepted Answer

The activation energy of the reaction

Question 17

Which of the following statements about catalysts is correct?

Accepted Answer

A catalyst lowers the activation energy but does not affect the equilibrium position.

Question 18

A reaction is exothermic ($$\Delta H^\circ \u003c 0). $$According to Le Châtelier's principle, what happens to the equilibrium if the temperature is increased?

Accepted Answer

The equilibrium shifts toward the reactants.

Question 19

A student mixes 0.1 M $$HCl$$ with 0.1 M $$NaOH. $$What will the pH of the resulting solution be?

Accepted Answer

pH = 7

CHE 1102 Final Exam Review: General Chemistry II Core Concepts

Guida di studio - Domande di pratica

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