Q: A student prepares 250 mL of a 0.5 M NaCl solution. How many grams of NaCl are required? ($$M_{NaCl} = 58.44 \ g/mol)$$

$$0.5 \times 0.250 \times 58.44 = 7.305 \ g$$

Q: You have 100 mL of 2.0 M HCl and want to dilute it to 0.5 M. What will be the final volume after dilution?

$$V_2$$ = \frac{M_1V_1}{$$M_2$$} = \frac{2.0 \times 100}{0.5} = 400 \ mL$$

Q: A solution is prepared by dissolving 5.00 g of glucose ($$C_6H_{12}O_6$) in enough water to make 100 mL of solution. What is the molarity? (M$$_{C_6H_{12}$$O_6$$} = 180.16 \ g/mol$)

$$M = \frac{5.00}{180.16 \times 0.100} = 0.277 \ M$$

Q: A chemist mixes 50 mL of 1.0 M NaOH with 150 mL of water. What is the final concentration of NaOH?

$$M_2$$ = \frac{M_1V_1}{$$V_2$$} = \frac{1.0 \times 50}{200} = 0.25 \ M$$

Q: A 2.0 L container holds 0.5 mol of oxygen gas at 300 K. What is the pressure inside the container? ($$R = 0.0821 \ L \cdot atm \cdot $$mol^{-1}$$ \cdot K$$^{-1}$$)

$$P = \frac{nRT}{V} = \frac{0.5 \times 0.0821 \times 300}{2.0} = 6.1575 \ atm$$

Q: A sample of gas at 1.0 atm and 273 K occupies 22.4 L. How many moles of gas are present?

$$n = \frac{PV}{RT} = \frac{1.0 \times 22.4}{0.0821 \times 273} = 1.00 \ mol$$

Q: A gas occupies 3.0 L at 2.0 atm. If the pressure is increased to 6.0 atm at constant temperature, what is the new volume?

$$V_2$$ = \frac{P_1V_1}{$$P_2$$} = \frac{2.0 \times 3.0}{6.0} = 1.0 \ L$$

Question 1

Which of the following correctly defines molarity ($$M) of a $$solution?

Accepted Answer

The number of moles of solute per liter of solution.

Question 2

A student prepares 250 mL of a 0.5 M NaCl solution. How many grams of NaCl are required? ($$M_{NaCl} = 58.44 \ g/mol)$$

Accepted Answer

$$0.5 	imes 0.250 	imes 58.44 = 7.305 \ g$$

Question 3

Which equation is used to calculate the dilution of a solution?

Accepted Answer

$$M_1V_1 = M_2V_2$$

Question 4

You have 100 mL of 2.0 M HCl and want to dilute it to 0.5 M. What will be the final volume after dilution?

Accepted Answer

$$V_2$$ = \frac{M_1V_1}{$$M_2$$} = \frac{2.0 	imes 100}{0.5} = 400 \ mL$$

Question 5

A solution is prepared by dissolving 5.00 g of glucose ($$C_6H_{12}O_6$) in enough water to make 100 mL of solution. What is the molarity? (M$$_{C_6H_{12}$$O_6$$} = 180.16 \ g/mol$)

Accepted Answer

$$M = \frac{5.00}{180.16 	imes 0.100} = 0.277 \ M$$

Question 6

Which of the following is NOT a unit of concentration?

Accepted Answer

Density ($$\rho)$$

Question 7

A chemist mixes 50 mL of 1.0 M NaOH with 150 mL of water. What is the final concentration of NaOH?

Accepted Answer

$$M_2$$ = \frac{M_1V_1}{$$V_2$$} = \frac{1.0 	imes 50}{200} = 0.25 \ M$$

Question 8

Which of the following best describes a limiting reactant in a chemical reaction?

Accepted Answer

The reactant that determines the amount of product formed.

Question 9

If 0.50 mol of $$AgNO_3$$ reacts with 0.30 mol of $$NaCl$$ according to $$AgNO_3 + $$NaCl \rightarrow AgCl + $$NaNO_3$$, which is the limiting reactant?

Accepted Answer

$$NaCl$$

Question 10

Which equation represents the ideal gas law?

Accepted Answer

$$PV = nRT$$

Question 11

A 2.0 L container holds 0.5 mol of oxygen gas at 300 K. What is the pressure inside the container? ($$R = 0.0821 \ L \cdot atm \cdot $$mol^{-1}$$ \cdot K$$^{-1}$$)

Accepted Answer

$$P = \frac{nRT}{V} = \frac{0.5 	imes 0.0821 	imes 300}{2.0} = 6.1575 \ atm$$

Question 12

Which of the following is a correct rearrangement of the ideal gas law to solve for the number of moles ($$n$$)?

Accepted Answer

$$n = \frac{PV}{RT}$$

Question 13

A sample of gas at 1.0 atm and 273 K occupies 22.4 L. How many moles of gas are present?

Accepted Answer

$$n = \frac{PV}{RT} = \frac{1.0 	imes 22.4}{0.0821 	imes 273} = 1.00 \ mol$$

Question 14

Which of the following is a gas law that relates pressure and volume at constant temperature?

Accepted Answer

Boyle's Law: $$P_1V_1 = P_2V_2$$

Question 15

A gas occupies 3.0 L at 2.0 atm. If the pressure is increased to 6.0 atm at constant temperature, what is the new volume?

Accepted Answer

$$V_2$$ = \frac{P_1V_1}{$$P_2$$} = \frac{2.0 	imes 3.0}{6.0} = 1.0 \ L$$

Question 16

Which of the following is a correct combined gas law equation?

Accepted Answer

$$\frac{P_1V_1}{T_1$} = \frac{P_2V_2}{T_2$}$$

Question 17

A hospital uses a tank containing 10.0 L of oxygen gas at 5.0 atm and 300 K. If the gas is released into a room at 1.0 atm and 300 K, what volume will it occupy?

Accepted Answer

$$V_2$$ = \frac{P_1V_1}{$$P_2$$} = \frac{5.0 	imes 10.0}{1.0} = 50.0 \ L$$

Question 18

Which of the following is a correct application of the gas law to calculate the final pressure when volume and temperature change?

Accepted Answer

$$P_2$$ = $$P_1$$ \frac{$$V_1$$}{$$V_2$$} \frac{$$T_2$$}{$$T_1$$}$$

General Chemistry Study Notes: Solution Stoichiometry and Gas Laws

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