Q: A solution is prepared by dissolving 10.0 g of NaCl in enough water to make 500.0 mL of solution. What is the molarity of the solution? (Molar mass of NaCl = 58.44 g/mol)

$$M = \frac{10.0}{58.44 \times 0.500} = 0.342\ \text{M}$$

Q: A patient’s blood pH is measured at 7.25. What is the hydronium ion concentration $$[H_3O^+] in $$the blood?

$$[H_3O^+] = 10$$^{-7.25}$$ = 5.62 \times 10$$^{-8}$$\ \text{M}$$

Q: A gas occupies 2.50 L at 1.00 atm and 300 K. What volume will it occupy at 2.00 atm and 300 K? (Assume ideal gas behavior.)

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{1.00 \times 2.50}{2.00} = 1.25\ \text{L}$$

Q: What is the percent by mass (% m/m) of NaCl in a solution prepared by dissolving 5.0 g of NaCl in 45.0 g of water?

$$\%\ m/m = \frac{5.0}{5.0 + 45.0} \times 100 = 10\%$$

Q: A 250 mL sample of 0.40 M HCl is diluted to 1.00 L. What is the final concentration?

$$M_d = \frac{M_c V_c}{V_d} = \frac{0.40 \times 250}{1000} = 0.10\ \text{M}$$

Q: A sample of gas has a mass of 2.00 g and occupies a volume of 1.00 L. What is its density?

$$D = \frac{2.00}{1.00} = 2.00\ \text{g/L}$$

Q: A solution contains 0.0050 g of lead(II) ion in 1.0 L of water. What is the concentration in ppm?

$$ppm = \frac{0.0050}{1.0} \times 10^6$ = 5.0 \times 10^3$

Q: A sample of gas at 25°C and 1 atm contains 0.50 mol. What is its volume according to the ideal gas law?

$$V = \frac{nRT}{P} = \frac{0.50 \times 0.08206 \times 298}{1.00} = 12.2\ \text{L}$$

Question 1

Which of the following statements best describes the difference between a polar covalent bond and an ionic bond, according to electronegativity differences?

Accepted Answer

A polar covalent bond involves electrons being shared unequally between atoms with a moderate electronegativity difference, while an ionic bond involves electrons being transferred between atoms with a large electronegativity difference.

Question 2

A solution is prepared by dissolving 10.0 g of NaCl in enough water to make 500.0 mL of solution. What is the molarity of the solution? (Molar mass of NaCl = 58.44 g/mol)

Accepted Answer

$$M = \frac{10.0}{58.44 	imes 0.500} = 0.342\ 	ext{M}$$

Question 3

Which of the following compounds is an example of a ketone?

Accepted Answer

CH3COCH3

Question 4

A patient’s blood pH is measured at 7.25. What is the hydronium ion concentration $$[H_3O^+] in $$the blood?

Accepted Answer

$$[H_3O^+] = 10$$^{-7.25}$$ = 5.62 	imes 10$$^{-8}$$\ 	ext{M}$$

Question 5

Which of the following best describes the functional group present in an amide?

Accepted Answer

-CONH2

Question 6

A gas occupies 2.50 L at 1.00 atm and 300 K. What volume will it occupy at 2.00 atm and 300 K? (Assume ideal gas behavior.)

Accepted Answer

$$V_2$$ = \frac{$$P_1$$ $$V_1$$}{$$P_2$$} = \frac{1.00 	imes 2.50}{2.00} = 1.25\ 	ext{L}$$

Question 7

Which of the following acids is considered a strong acid and is completely dissociated in water?

Accepted Answer

Hydrochloric acid ($$HCl)$$

Question 8

What is the percent by mass (% m/m) of NaCl in a solution prepared by dissolving 5.0 g of NaCl in 45.0 g of water?

Accepted Answer

$$\%\ m/m = \frac{5.0}{5.0 + 45.0} 	imes 100 = 10\%$$

Question 9

Which of the following elements has the highest electronegativity according to the Pauling scale?

Accepted Answer

Fluorine

Question 10

A 250 mL sample of 0.40 M HCl is diluted to 1.00 L. What is the final concentration?

Accepted Answer

$$M_d = \frac{M_c V_c}{V_d} = \frac{0.40 	imes 250}{1000} = 0.10\ 	ext{M}$$

Question 11

Which of the following best describes the relationship between pH and pOH in aqueous solution at 25°C?

Accepted Answer

$$pH + pOH = 14$$

Question 12

A sample of gas has a mass of 2.00 g and occupies a volume of 1.00 L. What is its density?

Accepted Answer

$$D = \frac{2.00}{1.00} = 2.00\ 	ext{g/L}$$

Question 13

Which of the following is the correct formula for calculating the standard free energy change ($$\Delta G^o$$)?

Accepted Answer

$$\Delta G^o = \Delta H^o - T\Delta S^o$$

Question 14

Which of the following organic compounds contains a carboxylic acid functional group?

Accepted Answer

CH3COOH

Question 15

A solution contains 0.0050 g of lead(II) ion in 1.0 L of water. What is the concentration in ppm?

Accepted Answer

$$ppm = \frac{0.0050}{1.0} 	imes 10^6$ = 5.0 	imes 10^3$

Question 16

Which of the following best describes the conjugate base of sulfuric acid ($$H_2SO_4$$)?

Accepted Answer

HSO$$_4^-$$

Question 17

A sample of gas at 25°C and 1 atm contains 0.50 mol. What is its volume according to the ideal gas law?

Accepted Answer

$$V = \frac{nRT}{P} = \frac{0.50 	imes 0.08206 	imes 298}{1.00} = 12.2\ 	ext{L}$$

Question 18

Which of the following is the correct formula for converting Celsius to Kelvin?

Accepted Answer

$$T_K = T_C + 273.15$$

Question 19

Which of the following best describes the bond type in NaCl?

Accepted Answer

Ionic

Comprehensive Study Notes: Key Equations and Concepts for Introductory Chemistry

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