Q: A nurse needs to prepare 250 mL of a 0.45% (m/v) NaCl solution. How many grams of NaCl are required?

$$0.45\ \%\ (m/v) = \frac{0.45\ \text{g}}{100\ \text{mL}}$$ $$\text{Required grams} = 0.45\ \text{g} \times \frac{250\ \text{mL}}{100\ \text{mL}} = 1.125\ \text{g}$$

Q: Which equation correctly relates pH and hydronium ion concentration?

$$\text{pH} = -\log_{10}[\text{H}_3\text{O}^+]$$

Q: A solution has a hydronium ion concentration of $$1 \times 10$$^{-4}$$ M. What is its pH?

$$\text{pH} = -\log_{10}(1 \times 10$$^{-4}$$) = 4$$

Question 1

Which of the following best describes a solution?

Accepted Answer

A homogeneous mixture of two or more substances where the solute is uniformly distributed within the solvent.

Question 2

A nurse needs to prepare 250 mL of a 0.45% (m/v) NaCl solution. How many grams of NaCl are required?

Accepted Answer

$$0.45\ \%\ (m/v) = \frac{0.45\ 	ext{g}}{100\ 	ext{mL}}$$ 
$$	ext{Required grams} = 0.45\ 	ext{g} 	imes \frac{250\ 	ext{mL}}{100\ 	ext{mL}} = 1.125\ 	ext{g}$$

Question 3

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

Accepted Answer

$$M_1V_1 = M_2V_2$$

Question 4

Which of the following best describes the difference between a solution, a colloid, and a suspension?

Accepted Answer

Solution particles are molecular-sized and do not settle; colloid particles are larger and scatter light but do not settle; suspension particles are largest and settle out upon standing.

Question 5

What happens to red blood cells when placed in a hypertonic solution?

Accepted Answer

They shrink due to water leaving the cell by osmosis.

Question 6

Which of the following statements about diffusion and osmosis is correct?

Accepted Answer

Diffusion is the movement of particles from high to low concentration; osmosis is the movement of water across a semipermeable membrane from low solute concentration to high solute concentration.

Question 7

Which of the following substances is most likely to dissolve in water?

Accepted Answer

CH$$_3F$$, because it is polar and can form hydrogen bonds with water.

Question 8

Which of the following is a strong electrolyte?

Accepted Answer

NaCl, because it completely dissociates into ions in water.

Question 9

What does it mean for a process to be at equilibrium?

Accepted Answer

The rates of the forward and reverse processes are equal, and the concentrations of reactants and products remain constant.

Question 10

Which equation correctly relates pH and hydronium ion concentration?

Accepted Answer

$$	ext{pH} = -\log_{10}[	ext{H}_3	ext{O}^+]$$

Question 11

A solution has a hydronium ion concentration of $$1 	imes 10$$^{-4}$$ M. What is its pH?

Accepted Answer

$$	ext{pH} = -\log_{10}(1 	imes 10$$^{-4}$$) = 4$$

Question 12

Which of the following pairs represents an acid and its conjugate base?

Accepted Answer

H$$_2PO$_4^-$$ and HPO$$_4$$^{2-}$$

Question 13

What is the dissociation reaction for NaCl in water?

Accepted Answer

$$	ext{NaCl} ightarrow 	ext{Na}^+ + 	ext{Cl}^-$$

Question 14

How many mL of 0.45% (m/v) NaCl solution can be made from 25.0 g of NaCl?

Accepted Answer

$$	ext{Volume} = \frac{25.0\ 	ext{g}}{0.45\ 	ext{g}/100\ 	ext{mL}} = \frac{25.0\ 	ext{g} 	imes 100\ 	ext{mL}}{0.45\ 	ext{g}} = 5556\ 	ext{mL}$$

Question 15

Which of the following best explains why CH$$_3F is $$more soluble in water than CCl$$_4$$?

Accepted Answer

CH$$_3F is $$polar and can form dipole-dipole interactions and hydrogen bonds with water, while CCl$$_4 is $$nonpolar and cannot interact strongly with water.

Question 16

Which of the following is a correct dissociation reaction for a strong acid in water?

Accepted Answer

$$	ext{HCl} + 	ext{H}_2	ext{O} ightarrow 	ext{H}_3	ext{O}^+ + 	ext{Cl}^-$$

Question 17

Which of the following best describes a buffer?

Accepted Answer

A solution that resists changes in pH when small amounts of acid or base are added, typically composed of a weak acid and its conjugate base.

Question 18

What is the balanced chemical equation when H$$_2PO$_4^-/$$HPO$$_4$$^{2-}$$ buffer reacts with added acid (H$$^+$$)?

Accepted Answer

$$	ext{HPO}_4$$^{2-}$$ + 	ext{H}^+ ightarrow 	ext{H}_2	ext{PO}_4^-$$

Question 19

Which of the following hydrocarbons is unsaturated?

Accepted Answer

CH$$_2=CH$_2 ($$ethylene)

Question 20

Which of the following is a combustion reaction for propane (C$$_3H$_8$$)?

Accepted Answer

$$	ext{C}_3	ext{H}_8 + 5\ 	ext{O}_2 ightarrow 3\ 	ext{CO}_2 + 4\ 	ext{H}_2	ext{O}$$

Comprehensive Study Notes: Solutions, Acids & Bases, and Hydrocarbons

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