Question 1

A weather balloon is filled with 6.34 g of helium (He). The balloon is 1.85 L and is held at 23°C. What is the density of the helium in the balloon in g/L?

Accepted Answer

$$3.43\ \mathrm{g/L}$$

Question 2

A 0.350 mol sample of gas occupies 7.24 L. What volume will 0.572 mol occupy under the same conditions?

Accepted Answer

$$11.8\ \mathrm{L}$$

Question 3

A balloon is filled with helium gas. The balloon is 983 mL in a chamber held at a constant temperature and 6.57 atm. If the chamber decreases pressure to 798 mm Hg, what is the resulting volume in L? (1 atm = 760 mm Hg)

Accepted Answer

$$7.98\ \mathrm{L}$$

Question 4

A balloon is filled with xenon (Xe) in a chamber held at $$27.3^\circ\mathrm{C}$$ and $$1600\ \mathrm{mm\ Hg}. $$The balloon is $$2.36\ \mathrm{L}. $$How many grams of xenon was the balloon filled with? ($$R = 0.0821\ \mathrm{L\ atm\ $$mol^{-1}$$\ K$$^{-1}$$}$$, $$M_{Xe} = 131.3\ \mathrm{g/mol})$$

Accepted Answer

$$20.1\ \mathrm{g}$$

Question 5

A mixture contains $$2.3$$ mol of nitrogen ($$\mathrm{N}_2) $$and $$0.46$$ mol of oxygen ($$\mathrm{O}_2). $$What is the mole fraction of oxygen in the mixture?

Accepted Answer

$$0.167$$

Question 6

A solution is formed by breaking solute-solute interactions and solvent-solvent interactions, each requiring $$+54.2\ \mathrm{kJ}$$ and $$+90.7\ \mathrm{kJ}$$, respectively. The formation of the solute-solvent interactions is $$-114.9\ \mathrm{kJ}. $$What is the enthalpy of solution, and is the process endothermic or exothermic?

Accepted Answer

$$+30.0\ \mathrm{kJ}$$, endothermic

Question 7

Which of the following gases will diffuse the fastest at $$300\ \mathrm{K}$$? (Molar masses: $$\mathrm{Br}_2 = 159.8\ \mathrm{g/mol}$$, $$\mathrm{H}_2\mathrm{S} = 34.1\ \mathrm{g/mol}$$, $$\mathrm{NH}_3 = 17.0\ \mathrm{g/mol}$$, $$\mathrm{C}_4\mathrm{H}_{10} = 58.1\ \mathrm{g/mol})$$

Accepted Answer

$$\mathrm{NH}_3$$

Question 8

A solution is made with $$23\ \mathrm{g} of $$glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6) $$and $$70\ \mathrm{g} of $$water ($$\mathrm{H}_2\mathrm{O}). $$What is the molality of the solution?

Accepted Answer

$$1.83\ \mathrm{mol/kg}$$

Question 9

Which of the following statements about intermolecular forces (IMFs) is correct?

Accepted Answer

Hydrogen bonding is stronger than London dispersion forces but weaker than ionic bonds.

Question 10

A solution is prepared by dissolving $$18.6\ \mathrm{g} of $$glucose ($$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6) in$$ $$250.0\ \mathrm{g} of $$water. The boiling point elevation constant for water is $$K_b = 0.512^\circ\mathrm{C}/m. $$What is the boiling point of the solution? (Molar mass of glucose = $$180.2\ \mathrm{g/mol}$$, boiling point of pure water = $$100.0^\circ\mathrm{C})$$

Accepted Answer

$$100.212^\circ\mathrm{C}$$

Question 11

A red blood cell is placed in a hypertonic solution. What will happen to the cell?

Accepted Answer

It will shrink as water leaves the cell.

Question 12

Which of the following pairs of compounds will form a solution based on their polarity?

Accepted Answer

Water ($$\mathrm{H}_2\mathrm{O}) $$and methanol ($$\mathrm{C}_2\mathrm{H}_5\mathrm{OH})$$

Question 13

A solution is made with $$0.506\ \mathrm{g} of $$sodium hydroxide ($$\mathrm{NaOH}$$), which makes up $$3.20\% of $$the solution’s mass. What is the mass of the solution?

Accepted Answer

$$15.8\ \mathrm{g}$$

Question 14

Which of the following best describes the process of vapor pressure lowering in a solution?

Accepted Answer

The vapor pressure of a solution is lower than that of the pure solvent due to the presence of nonvolatile solute particles.

Question 15

A 3.43 mL bubble forms at a depth of 120 m below sea level. At this depth, the temperature is $$-12^\circ\mathrm{C}. $$Every 10 m, the pressure increases by 1.06 atm. The temperature at sea-level is $$14^\circ\mathrm{C}. $$What is the volume of the bubble when it reaches the surface (sea-level)? (Assume atmospheric pressure is 1 atm.)

Accepted Answer

$$44.6\ \mathrm{mL}$$

Question 16

Which of the following statements about electrolytes is correct?

Accepted Answer

Strong electrolytes dissociate completely in water, while weak electrolytes only partially dissociate.

Question 17

A solution is prepared by dissolving $$3.872\ \mathrm{g} of $$lithium fluoride ($$\mathrm{LiF}) in $$enough water to make $$231.7\ \mathrm{mL} of $$solution. What is the molarity of the solution? (Molar mass of $$\mathrm{LiF} = 25.94\ \mathrm{g/mol})$$

Accepted Answer

$$0.648\ \mathrm{M}$$

Question 18

Which of the following phase changes is exothermic?

Accepted Answer

Condensation

Question 19

A solution is prepared by dissolving $$4.80\ \mathrm{g} of an $$unknown ionic compound in $$130.0\ \mathrm{g} of$$ $$\mathrm{H}_2\mathrm{O}. $$The freezing point is measured to be $$-1.72^\circ\mathrm{C}. $$What is the van’t Hoff factor, if the molar mass of the ionic compound is $$120.0\ \mathrm{g/mol}$$ and $$K_f = 1.86^\circ\mathrm{C}/m$$?

Accepted Answer

$$2.0$$

General Chemistry Study Guide: Gas Laws, Intermolecular Forces, and Solutions

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