Quiz: Solutions and Ideal Gases — 18 questions

Question 1

1. Which expression gives the mass of solute needed to prepare a solution of concentration $C_{\text{solute}}$ and volume $V_{\text{solution}}$ ?

m_{\text{solute}}=\frac{C_{\text{solute}}M_{\text{solute}}}{V_{\text{solution}}}

m_{\text{solute}}=C_{\text{solute}}+V_{\text{solution}}+M_{\text{solute}}

m_{\text{solute}}=C_{\text{solute}}V_{\text{solution}}M_{\text{solute}}

m_{\text{solute}}=\frac{V_{\text{solution}}}{C_{\text{solute}}M_{\text{solute}}}

Explanation

The required mass equals the amount of solute multiplied by its molar mass, with the amount given by concentration times solution volume. Dividing by volume would produce the wrong dependence because a larger final volume requires more solute at fixed concentration.

Answer

$$m_{\text{solute}}=C_{\text{solute}}V_{\text{solution}}M_{\text{solute}}$$

Question 2

2. A student begins with a measured mass of a solid compound and dissolves it in a chosen volume of solvent; which preparation method is being used?

Preparation by dissolution

Concentration by evaporation

Preparation by dilution

Separation by filtration

Explanation

Dissolution prepares a solution by determining the required mass of a solid solute and dissolving it in the selected solvent volume. Dilution instead begins with a mother solution and uses it to make a less concentrated daughter solution.

Answer

Preparation by dissolution

Question 3

3. What happens to an ionic solid when it dissolves in water?

Its solute amount changes into a different chemical element

Its solution volume becomes equal to its solute mass

Its solid structure separates into aqueous ions

Its particles remain as solid units suspended in water

Explanation

Water separates the ions that made up the ionic solid, producing aqueous ions throughout the solution. A dilution changes concentration by adding solvent but does not describe this separation into new aqueous ions.

Answer

Its solid structure separates into aqueous ions

Question 4

4. Which aqueous equation correctly represents the dissolution of iron(III) chloride?

\mathrm{FeCl_3(aq)}\xrightarrow{\text{water}}\mathrm{Fe^{3-}(aq)}+3\mathrm{Cl^+(aq)}

\mathrm{FeCl_3(s)}\xrightarrow{\text{water}}\mathrm{Fe^{2+}(aq)}+3\mathrm{Cl^-(aq)}

\mathrm{FeCl_3(s)}\xrightarrow{\text{water}}\mathrm{Fe^{+}(aq)}+\mathrm{Cl_3^{3-}(aq)}

\mathrm{FeCl_3(s)}\xrightarrow{\text{water}}\mathrm{Fe^{3+}(aq)}+3\mathrm{Cl^-(aq)}

Explanation

Each formula unit of iron(III) chloride produces one $\mathrm{Fe^{3+}}$ ion and three $\mathrm{Cl^-}$ ions in water. The formula $\mathrm{FeCl_3}$ represents the solid compound, not an aqueous ion with a combined charge.

Answer

$$\mathrm{FeCl_3(s)}\xrightarrow{\text{water}}\mathrm{Fe^{3+}(aq)}+3\mathrm{Cl^-(aq)}$$

Question 5

5. If an iron(III) chloride solution has concentration $C(\mathrm{FeCl_3})=0.20\,\mathrm{mol\,L^{-1}}$ , what is its chloride ion concentration?

0.067\,\mathrm{mol\,L^{-1}}

0.40\,\mathrm{mol\,L^{-1}}

0.20\,\mathrm{mol\,L^{-1}}

0.60\,\mathrm{mol\,L^{-1}}

Explanation

Each dissolved $\mathrm{FeCl_3}$ unit produces three chloride ions, so $[\mathrm{Cl^-}]=3C(\mathrm{FeCl_3})=3\times0.20=0.60\,\mathrm{mol\,L^{-1}}$ . The value $0.20\,\mathrm{mol\,L^{-1}}$ would describe the iron(III) ion concentration instead.

Answer

$$0.60\,\mathrm{mol\,L^{-1}}$$

Question 6

6. A mother solution is diluted without losing solute. Which relationship connects the mother and daughter solutions?

C_{\text{daughter}}V_{\text{mother}}=C_{\text{mother}}V_{\text{daughter}}

\frac{C_{\text{daughter}}}{V_{\text{daughter}}}=\frac{C_{\text{mother}}}{V_{\text{mother}}}

C_{\text{daughter}}+V_{\text{daughter}}=C_{\text{mother}}+V_{\text{mother}}

C_{\text{daughter}}V_{\text{daughter}}=C_{\text{mother}}V_{\text{mother}}

Explanation

Dilution conserves the amount of solute, which is represented by concentration multiplied by volume on each side. The daughter concentration decreases because its volume increases while this product remains constant.

Answer

$$C_{\text{daughter}}V_{\text{daughter}}=C_{\text{mother}}V_{\text{mother}}$$

Question 7

7. A dilution produces a daughter solution with volume $V_{\text{daughter}}$ from a mother solution volume $V_{\text{mother}}$ ; how is the dilution factor defined?

F=C_{\text{mother}}+C_{\text{daughter}}+V_{\text{daughter}}+V_{\text{mother}}

F=\frac{V_{\text{mother}}}{V_{\text{daughter}}}=\frac{C_{\text{mother}}}{C_{\text{daughter}}}

F=\frac{V_{\text{daughter}}}{V_{\text{mother}}}=\frac{C_{\text{daughter}}}{C_{\text{mother}}}

F=\frac{V_{\text{daughter}}}{V_{\text{mother}}}=\frac{C_{\text{mother}}}{C_{\text{daughter}}}

Explanation

The dilution factor compares the daughter and mother volumes, equivalently the mother and daughter concentrations. The concentration ratio must be inverted relative to the volume ratio because dilution lowers concentration as volume increases.

Answer

$$F=\frac{V_{\text{daughter}}}{V_{\text{mother}}}=\frac{C_{\text{mother}}}{C_{\text{daughter}}}$$

Question 8

8. What does a 0.9% saline solution contain in every 100 g of solution?

0.9 g of water vapor

9.0 g of dissolved salt

0.9 g of dissolved salt

90 g of dissolved salt

Explanation

Mass percentage specifies the mass of solute present in 100 g of solution, so the solution contains 0.9 g of salt in that basis. A concentration measure does not necessarily use 100 g of solution as its reference amount.

Answer

0.9 g of dissolved salt

Question 9

9. How does mass percentage differ from mass fraction for the same solution?

Mass percentage is the mass fraction divided by 100 and expressed without units.

Mass percentage is the mass fraction multiplied by 100 and expressed in percent.

Mass percentage uses solute volume, whereas mass fraction uses solution volume.

Mass percentage measures density, whereas mass fraction measures total solution mass.

Explanation

The mass fraction is the dimensionless ratio of solute mass to solution mass, while mass percentage multiplies that ratio by 100 and reports it as a percentage. A mass fraction is therefore not obtained by dividing the percentage by another mass-based quantity.

Answer

Mass percentage is the mass fraction multiplied by 100 and expressed in percent.

Question 10

10. Which description best matches the ideal-gas model?

Gas particles are closely packed, with strong attractions and a fixed collective volume.

Gas particles are far apart, with negligible interactions and negligible total particle volume.

Gas particles occupy most of the container, with collisions that reduce their kinetic energy.

Gas particles have moderate spacing, with interactions that determine their boiling point.

Explanation

The ideal-gas model treats particles as sufficiently separated that their interactions and combined proper volume are negligible compared with the gas volume. Strong particle attractions and substantial particle volume are characteristics that make real gases depart from this model.

Answer

Gas particles are far apart, with negligible interactions and negligible total particle volume.

Question 11

11. A gas sample has pressure $P$ , volume $V$ , amount $n$ , and absolute temperature $T$ ; which equation relates these quantities for an ideal gas?

P+V=nRT

PV=nRT

P=nVRT

PV=\frac{n}{RT}

Explanation

The ideal-gas law states that pressure times volume equals amount of substance times the gas constant and absolute temperature. The other expressions do not preserve the required relationships among these variables.

Answer

$$PV=nRT$$

Question 12

12. What does the molar volume $V_m$ of an ideal gas represent?

The pressure required to compress one mole of the gas

The total volume occupied by the entire gas sample

The volume occupied by one mole of the gas

The mass contained in one liter of the gas

Explanation

Molar volume is defined as the volume occupied by one mole and is given for an ideal gas by $V_m=\frac{RT}{P}$ . The total sample volume depends on how many moles are present and is therefore distinct from molar volume.

Answer

The volume occupied by one mole of the gas

Question 13

13. At fixed temperature and pressure, how can the amount of gas be calculated from its volume and molar volume?

n=\frac{V}{V_m}

n=\frac{V_m}{V}

n=V+V_m

n=V V_m

Explanation

At fixed temperature and pressure, dividing the sample volume by the volume occupied per mole gives the amount of substance. Multiplying or reversing the ratio would produce the wrong dependence on sample volume and molar volume.

Answer

$$n=\frac{V}{V_m}$$

Question 14

14. What is the molar volume of an ideal gas at 20 °C and 1013 hPa?

1013 L mol⁻¹

22.4 L mol⁻¹

20.0 L mol⁻¹

24.1 L mol⁻¹

Explanation

At 20 °C and 1013 hPa, the molar volume is 24.1 L mol⁻¹. The value 22.4 L mol⁻¹ applies at 0 °C and 1013 hPa, so it corresponds to different conditions.

Answer

24.1 L mol⁻¹

Question 15

15. Why is hydrochloric acid added in excess when determining the calcium carbonate content of soil?

To increase the molar mass of the sample

To convert calcium carbonate into oxygen

To ensure that all calcium carbonate reacts

To prevent carbon dioxide from dissolving

Explanation

Excess hydrochloric acid promotes complete reaction of the calcium carbonate, allowing the released carbon dioxide to represent the full carbonate content. Using too little acid could leave some calcium carbonate unreacted and produce an underestimated result.

Answer

To ensure that all calcium carbonate reacts

Question 16

16. What amount of carbon dioxide corresponds to a volume of 72 mL at 20 °C and 1013 hPa, using a molar volume of 24.1 L mol⁻¹?

7.2\times10^{-2}\,\mathrm{mol}

2.4\times10^{-2}\,\mathrm{mol}

3.0\times10^{-1}\,\mathrm{mol}

3.0\times10^{-3}\,\mathrm{mol}

Explanation

Converting 72 mL to 0.072 L and dividing by 24.1 L mol⁻¹ gives $n_{\mathrm{CO_2}}=3.0\times10^{-3}\,\mathrm{mol}$ . The larger values result from failing to apply the volume conversion or from using an incorrect relationship.

Answer

$$3.0\times10^{-3}\,\mathrm{mol}$$

Question 17

17. Given $n_{\mathrm{CO_2}}=3.0\times10^{-3}\,\mathrm{mol}$ and a one-to-one reaction ratio, what mass of calcium carbonate is produced?

1.20\,\mathrm{g}

0.30\,\mathrm{g}

0.025\,\mathrm{g}

3.00\,\mathrm{g}

Explanation

The stoichiometry gives the calcium carbonate amount as $3.0\times10^{-3}\,\mathrm{mol}$ , and multiplying by its molar mass gives a mass of $0.30\,\mathrm{g}$ . The value of $1.20\,\mathrm{g}$ refers to the original soil sample rather than the calcium carbonate it contains.

Answer

$$0.30\,\mathrm{g}$$

Question 18

18. If a 1.2 g soil sample contains 0.30 g of calcium carbonate, what is the calcium carbonate mass percentage?

40%

4.0%

25%

75%

Explanation

The mass percentage is calculated as $\frac{0.30}{1.2}\times100=25\%$ . A value such as 40% results from reversing or misapplying the masses in the percentage calculation.

Quiz: Solutions and Ideal Gases — 18 questions

Detailed questions and answers

1. Which expression gives the mass of solute needed to prepare a solution of concentration $C_{\text{solute}}$ and volume $V_{\text{solution}}$ ?

2. A student begins with a measured mass of a solid compound and dissolves it in a chosen volume of solvent; which preparation method is being used?

3. What happens to an ionic solid when it dissolves in water?

4. Which aqueous equation correctly represents the dissolution of iron(III) chloride?

5. If an iron(III) chloride solution has concentration $C(\mathrm{FeCl_3})=0.20\,\mathrm{mol\,L^{-1}}$ , what is its chloride ion concentration?

6. A mother solution is diluted without losing solute. Which relationship connects the mother and daughter solutions?

7. A dilution produces a daughter solution with volume $V_{\text{daughter}}$ from a mother solution volume $V_{\text{mother}}$ ; how is the dilution factor defined?

8. What does a 0.9% saline solution contain in every 100 g of solution?

9. How does mass percentage differ from mass fraction for the same solution?

10. Which description best matches the ideal-gas model?

11. A gas sample has pressure $P$ , volume $V$ , amount $n$ , and absolute temperature $T$ ; which equation relates these quantities for an ideal gas?

12. What does the molar volume $V_m$ of an ideal gas represent?

13. At fixed temperature and pressure, how can the amount of gas be calculated from its volume and molar volume?

14. What is the molar volume of an ideal gas at 20 °C and 1013 hPa?

15. Why is hydrochloric acid added in excess when determining the calcium carbonate content of soil?

16. What amount of carbon dioxide corresponds to a volume of 72 mL at 20 °C and 1013 hPa, using a molar volume of 24.1 L mol⁻¹?

17. Given $n_{\mathrm{CO_2}}=3.0\times10^{-3}\,\mathrm{mol}$ and a one-to-one reaction ratio, what mass of calcium carbonate is produced?

18. If a 1.2 g soil sample contains 0.30 g of calcium carbonate, what is the calcium carbonate mass percentage?

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Quiz: Solutions and Ideal Gases — 18 questions

Detailed questions and answers

1. Which expression gives the mass of solute needed to prepare a solution of concentration CsoluteC_{\text{solute}}Csolute​ and volume VsolutionV_{\text{solution}}Vsolution​?

2. A student begins with a measured mass of a solid compound and dissolves it in a chosen volume of solvent; which preparation method is being used?

3. What happens to an ionic solid when it dissolves in water?

4. Which aqueous equation correctly represents the dissolution of iron(III) chloride?

5. If an iron(III) chloride solution has concentration C(FeCl3)=0.20 mol L−1C(\mathrm{FeCl_3})=0.20\,\mathrm{mol\,L^{-1}}C(FeCl3​)=0.20molL−1, what is its chloride ion concentration?

6. A mother solution is diluted without losing solute. Which relationship connects the mother and daughter solutions?

7. A dilution produces a daughter solution with volume VdaughterV_{\text{daughter}}Vdaughter​ from a mother solution volume VmotherV_{\text{mother}}Vmother​; how is the dilution factor defined?

8. What does a 0.9% saline solution contain in every 100 g of solution?

9. How does mass percentage differ from mass fraction for the same solution?

10. Which description best matches the ideal-gas model?

11. A gas sample has pressure PPP, volume VVV, amount nnn, and absolute temperature TTT; which equation relates these quantities for an ideal gas?

12. What does the molar volume VmV_mVm​ of an ideal gas represent?

13. At fixed temperature and pressure, how can the amount of gas be calculated from its volume and molar volume?

14. What is the molar volume of an ideal gas at 20 °C and 1013 hPa?

15. Why is hydrochloric acid added in excess when determining the calcium carbonate content of soil?

16. What amount of carbon dioxide corresponds to a volume of 72 mL at 20 °C and 1013 hPa, using a molar volume of 24.1 L mol⁻¹?

17. Given nCO2=3.0×10−3 moln_{\mathrm{CO_2}}=3.0\times10^{-3}\,\mathrm{mol}nCO2​​=3.0×10−3mol and a one-to-one reaction ratio, what mass of calcium carbonate is produced?

18. If a 1.2 g soil sample contains 0.30 g of calcium carbonate, what is the calcium carbonate mass percentage?

Review with flashcards

Read the study sheet

Similar courses

Fondements de la science politique

Fondements de la biogéographie

Rappels sur les solutions et les gaz

Sociologie de l’éducation

Male Reproductive System Functions

Signaux périodiques et filtrage

Create your own quizzes

1. Which expression gives the mass of solute needed to prepare a solution of concentration $C_{\text{solute}}$ and volume $V_{\text{solution}}$ ?

5. If an iron(III) chloride solution has concentration $C(\mathrm{FeCl_3})=0.20\,\mathrm{mol\,L^{-1}}$ , what is its chloride ion concentration?

7. A dilution produces a daughter solution with volume $V_{\text{daughter}}$ from a mother solution volume $V_{\text{mother}}$ ; how is the dilution factor defined?

11. A gas sample has pressure $P$ , volume $V$ , amount $n$ , and absolute temperature $T$ ; which equation relates these quantities for an ideal gas?

12. What does the molar volume $V_m$ of an ideal gas represent?

17. Given $n_{\mathrm{CO_2}}=3.0\times10^{-3}\,\mathrm{mol}$ and a one-to-one reaction ratio, what mass of calcium carbonate is produced?