Dalton’s law of partial pressures

total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of the component gases

concentration unit defined as the ratio of the molar amount of a mixture component to the total number of moles of all mixture components

pressure exerted by an individual gas in a mixture

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Chemistry 2e · 9.3 Stoichiometry of Gaseous Substances, Mixtures, and Reactions

Stoichiometry of Gaseous Substances, Mixtures, and Reactions: practice problems

16 problems from the book, with its answers. Check your working, or have any of them explained to you on the whiteboard.

Exercises 49
Calculate the density of Freon 12, CF₂Cl₂, at 30.0 °C and 0.954 atm.
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Exercises 51
A cylinder of O₂(g) used in breathing by patients with emphysema has a volume of 3.00 L at a pressure of 10.0 atm. If the temperature of the cylinder is 28.0 °C, what mass of oxygen is in the cylinder?
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Exercises 53
What is the molar mass of a gas if 0.281 g of the gas occupies a volume of 125 mL at a temperature 126 °C and a pressure of 777 torr?
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Exercises 55
The density of a certain gaseous fluoride of phosphorus is 3.93 g/L at STP. Calculate the molar mass of this fluoride and determine its molecular formula.
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Exercises 57
A 36.0–L cylinder of a gas used for calibration of blood gas analyzers in medical laboratories contains 350 g CO₂, 805 g O₂, and 4,880 g N₂. At 25 degrees C, what is the pressure in the cylinder in atmospheres?
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Exercises 59
A sample of gas isolated from unrefined petroleum contains 90.0% CH₄, 8.9% C₂H₆, and 1.1% C₃H₈ at a total pressure of 307.2 kPa. What is the partial pressure of each component of this gas? (The percentages given indicate the percent of the total pressure that is due to each component.)
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Exercises 61
Most mixtures of hydrogen gas with oxygen gas are explosive. However, a mixture that contains less than 3.0 % O₂ is not. If enough O₂ is added to a cylinder of H₂ at 33.2 atm to bring the total pressure to 34.5 atm, is the mixture explosive?
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Exercises 63
A sample of carbon monoxide was collected over water at a total pressure of 756 torr and a temperature of 18 °C. What is the pressure of the carbon monoxide? (See Table 9.2 for the vapor pressure of water.)
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Exercises 65
Joseph Priestley first prepared pure oxygen by heating mercuric oxide, HgO:
$2 HgO (s) ⟶ 2 Hg (l) + O_{2} (g)$
(a) Outline the steps necessary to answer the following question: What volume of O₂ at 23 °C and 0.975 atm is produced by the decomposition of 5.36 g of HgO?
(b) Answer the question.
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Exercises 67
The chlorofluorocarbon CCl₂F₂ can be recycled into a different compound by reaction with hydrogen to produce CH₂F₂(g), a compound useful in chemical manufacturing:
$CCl_{2} F_{2} (g) + 4 H_{2} (g) ⟶ CH_{2} F_{2} (g) + 2 HCl (g)$
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Exercises 69
Lime, CaO, is produced by heating calcium carbonate, CaCO₃; carbon dioxide is the other product.
(a) Outline the steps necessary to answer the following question: What volume of carbon dioxide at 875 K and 0.966 atm is produced by the decomposition of 1 ton (1.000 $\times$ 10³ kg) of calcium carbonate?
(b) Answer the question.
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Exercises 71
Calculate the volume of oxygen required to burn 12.00 L of ethane gas, C₂H₆, to produce carbon dioxide and water, if the volumes of C₂H₆ and O₂ are measured under the same conditions of temperature and pressure.
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Exercises 73
Consider the following questions:
(a) What is the total volume of the CO₂(g) and H₂O(g) at 600 °C and 0.888 atm produced by the combustion of 1.00 L of C₂H₆(g) measured at STP?
(b) What is the partial pressure of H₂O in the product gases?
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Exercises 75
What volume of oxygen at 423.0 K and a pressure of 127.4 kPa is produced by the decomposition of 129.7 g of BaO₂ to BaO and O₂?
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Exercises 77
Ethanol, C₂H₅OH, is produced industrially from ethylene, C₂H₄, by the following sequence of reactions:
$3 C_{2} H_{4} + 2 H_{2} SO_{4} ⟶ C_{2} H_{5} HSO_{4} + (C_{2} H_{5})_{2} SO_{4}$
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Exercises 79
A sample of a compound of xenon and fluorine was confined in a bulb with a pressure of 18 torr. Hydrogen was added to the bulb until the pressure was 72 torr. Passage of an electric spark through the mixture produced Xe and HF. After the HF was removed by reaction with solid KOH, the final pressure of xenon and unreacted hydrogen in the bulb was 36 torr. What is the empirical formula of the xenon fluoride in the original sample? (Note: Xenon fluorides contain only one xenon atom per molecule.)
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Key terms · 4

Dalton’s law of partial pressures: total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of the component gases
mole fraction (X): concentration unit defined as the ratio of the molar amount of a mixture component to the total number of moles of all mixture components
partial pressure: pressure exerted by an individual gas in a mixture
vapor pressure of water: pressure exerted by water vapor in equilibrium with liquid water in a closed container at a specific temperature

Learn 9.3 on the whiteboard

The tutor teaches the whole section, drawing it out step by step and answering your questions as you go.

Read 9.3 in the textbook · This section on openstax.org

Stoichiometry of Gaseous Substances, Mixtures, and Reactions: practice problems

16 problems from the book, with its answers. Check your working, or have any of them explained to you on the whiteboard.

Exercises 49

Calculate the density of Freon 12, CF₂Cl₂, at 30.0 °C and 0.954 atm.

Exercises 51

A cylinder of O₂(g) used in breathing by patients with emphysema has a volume of 3.00 L at a pressure of 10.0 atm. If the temperature of the cylinder is 28.0 °C, what mass of oxygen is in the cylinder?

Exercises 53

What is the molar mass of a gas if 0.281 g of the gas occupies a volume of 125 mL at a temperature 126 °C and a pressure of 777 torr?

Exercises 55

The density of a certain gaseous fluoride of phosphorus is 3.93 g/L at STP. Calculate the molar mass of this fluoride and determine its molecular formula.

Exercises 57

A 36.0–L cylinder of a gas used for calibration of blood gas analyzers in medical laboratories contains 350 g CO₂, 805 g O₂, and 4,880 g N₂. At 25 degrees C, what is the pressure in the cylinder in atmospheres?

Exercises 59

A sample of gas isolated from unrefined petroleum contains 90.0% CH₄, 8.9% C₂H₆, and 1.1% C₃H₈ at a total pressure of 307.2 kPa. What is the partial pressure of each component of this gas? (The percentages given indicate the percent of the total pressure that is due to each component.)

Exercises 61

Most mixtures of hydrogen gas with oxygen gas are explosive. However, a mixture that contains less than 3.0 % O₂ is not. If enough O₂ is added to a cylinder of H₂ at 33.2 atm to bring the total pressure to 34.5 atm, is the mixture explosive?

Exercises 63

A sample of carbon monoxide was collected over water at a total pressure of 756 torr and a temperature of 18 °C. What is the pressure of the carbon monoxide? (See Table 9.2 for the vapor pressure of water.)

Exercises 65

Joseph Priestley first prepared pure oxygen by heating mercuric oxide, HgO:

$2 HgO (s) ⟶ 2 Hg (l) + O_{2} (g)$

(a) Outline the steps necessary to answer the following question: What volume of O₂ at 23 °C and 0.975 atm is produced by the decomposition of 5.36 g of HgO?

(b) Answer the question.

Exercises 67

The chlorofluorocarbon CCl₂F₂ can be recycled into a different compound by reaction with hydrogen to produce CH₂F₂(g), a compound useful in chemical manufacturing:

$CCl_{2} F_{2} (g) + 4 H_{2} (g) ⟶ CH_{2} F_{2} (g) + 2 HCl (g)$

Exercises 69

Lime, CaO, is produced by heating calcium carbonate, CaCO₃; carbon dioxide is the other product.

(a) Outline the steps necessary to answer the following question: What volume of carbon dioxide at 875 K and 0.966 atm is produced by the decomposition of 1 ton (1.000 $\times$ 10³ kg) of calcium carbonate?

(b) Answer the question.

Exercises 71

Calculate the volume of oxygen required to burn 12.00 L of ethane gas, C₂H₆, to produce carbon dioxide and water, if the volumes of C₂H₆ and O₂ are measured under the same conditions of temperature and pressure.

Exercises 73

Consider the following questions:

(a) What is the total volume of the CO₂(g) and H₂O(g) at 600 °C and 0.888 atm produced by the combustion of 1.00 L of C₂H₆(g) measured at STP?

(b) What is the partial pressure of H₂O in the product gases?

Exercises 75

What volume of oxygen at 423.0 K and a pressure of 127.4 kPa is produced by the decomposition of 129.7 g of BaO₂ to BaO and O₂?

Exercises 77

Ethanol, C₂H₅OH, is produced industrially from ethylene, C₂H₄, by the following sequence of reactions:

$3 C_{2} H_{4} + 2 H_{2} SO_{4} ⟶ C_{2} H_{5} HSO_{4} + (C_{2} H_{5})_{2} SO_{4}$

Exercises 79

A sample of a compound of xenon and fluorine was confined in a bulb with a pressure of 18 torr. Hydrogen was added to the bulb until the pressure was 72 torr. Passage of an electric spark through the mixture produced Xe and HF. After the HF was removed by reaction with solid KOH, the final pressure of xenon and unreacted hydrogen in the bulb was 36 torr. What is the empirical formula of the xenon fluoride in the original sample? (Note: Xenon fluorides contain only one xenon atom per molecule.)

Key terms · 4

Dalton’s law of partial pressures: total pressure of a mixture of ideal gases is equal to the sum of the partial pressures of the component gases
mole fraction (X): concentration unit defined as the ratio of the molar amount of a mixture component to the total number of moles of all mixture components
partial pressure: pressure exerted by an individual gas in a mixture
vapor pressure of water: pressure exerted by water vapor in equilibrium with liquid water in a closed container at a specific temperature

Learn 9.3 on the whiteboard

The tutor teaches the whole section, drawing it out step by step and answering your questions as you go.

Read 9.3 in the textbook · This section on openstax.org