1. CHEMISTRY Matter and Change
Chapter 13: Gases

2. Table Of Contents Section 13.1 The Gas Laws
CHAPTER13
Table Of Contents
Section The Gas Laws
Section The Ideal Gas Law
Section Gas Stoichiometry
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3. SECTION13.1
The Gas Laws
State the relationships among pressure, temperature, and volume of a constant amount of gas.
Apply the gas laws to problems involving the pressure, temperature, and volume of a constant amount of gas.
scientific law: describes a relationship in nature that is supported by many experiments

4. The Gas Laws Boyle’s law absolute zero Charles’s law Gay-Lussac’s law
SECTION13.1
The Gas Laws
Boyle’s law
absolute zero
Charles’s law
Gay-Lussac’s law
combined gas law
For a fixed amount of gas, a change in one variable—pressure, temperature, or volume—affects the other two.

5. P1V1 = P2V2 where P = pressure and V = volume
SECTION13.1
The Gas Laws
Boyle's Law
Boyle’s law states that the volume of a fixed amount of gas held at a constant temperature varies inversely with the pressure.
P1V1 = P2V2 where P = pressure and V = volume

6. The Gas Laws Charles's Law
SECTION13.1
The Gas Laws
Charles's Law
As temperature increases, so does the volume of gas when the amount of gas and pressure do not change.
Kinetic-molecular theory explains this property.

7. SECTION13.1
The Gas Laws
Charles's Law (cont.)

8. The Gas Laws Charles's Law (cont.)
SECTION13.1
The Gas Laws
Charles's Law (cont.)
Absolute zero is zero on the Kelvin scale.
Charles’s law states that the volume of a given amount of gas is directly proportional to its kelvin temperature at constant pressure.

9. The Gas Laws Gay-Lussac's Law
SECTION13.1
The Gas Laws
Gay-Lussac's Law
Gay-Lussac’s law states that the pressure of a fixed amount of gas varies directly with the kelvin temperature when the volume remains constant.

10. Gay-Lussac's Law (cont.)
SECTION13.1
The Gas Laws
Gay-Lussac's Law (cont.)

11. The Gas Laws The Combined Gas Law
SECTION13.1
The Gas Laws
The Combined Gas Law
The combined gas law states the relationship among pressure, temperature, and volume of a fixed amount of gas.

12. The Combined Gas Law (cont.)
SECTION13.1
The Gas Laws
The Combined Gas Law (cont.)

13. Boyle’s Law explains which relationship of properties in gases?
SECTION13.1
Section Check
Boyle’s Law explains which relationship of properties in gases?
A. pressure and volume
B. amount and pressure
C. temperature and volume
D. volume and temperature

14. Atoms are in their lowest energy state at what temperature?
SECTION13.1
Section Check
Atoms are in their lowest energy state at what temperature?
A. 0° Celsius
B. 0° Fahrenheit
C. –100° Celsius
D. 0 kelvin

16. SECTION13.2
The Ideal Gas Law
Relate number of particles and volume using Avogadro’s principle.
Relate the amount of gas present to its pressure, temperature, and volume using the ideal gas law.
Compare the properties of real and ideal gases.
mole: an SI base unit used to measure the amount of a substance; the amount of a pure substance that contains 6.02 × 1023 representative particles

17. The Ideal Gas Law Avogadro’s principle molar volume
SECTION13.2
The Ideal Gas Law
Avogadro’s principle
molar volume
ideal gas constant (R)
ideal gas law
The ideal gas law relates the number of particles to pressure, temperature, and volume.

18. The Ideal Gas Law Avogadro's Principle
SECTION13.2
The Ideal Gas Law
Avogadro's Principle
Avogadro’s principle states that equal volumes of gases at the same temperature and pressure contain equal numbers of particles.

19. Avogadro's Principle (cont.)
SECTION13.2
The Ideal Gas Law
Avogadro's Principle (cont.)
The molar volume of a gas is the volume 1 mol occupies at 0.00°C and 1.00 atm of pressure.
0.00°C and 1.00 atm are called standard temperature and pressure (STP).
At STP, 1 mol of gas occupies 22.4 L.

20. The Ideal Gas Law The Ideal Gas Law
SECTION13.2
The Ideal Gas Law
The Ideal Gas Law
Ideal gas particles occupy a negligible volume and are far enough apart to exert minimal attractive or repulsive forces on each other.
Combined gas law to ideal gas law

21. The Ideal Gas Law (cont.)
SECTION13.2
The Ideal Gas Law
The Ideal Gas Law (cont.)
The ideal gas constant is represented by R and is L•atm/mol•K when pressure is in atmospheres.
The ideal gas law describes the physical behavior of an ideal gas in terms of pressure, volume, temperature, and amount.

22. The Ideal Gas Law (cont.)
SECTION13.2
The Ideal Gas Law
The Ideal Gas Law (cont.)

23. The Ideal Gas Law—Molar Mass and Density
SECTION13.2
The Ideal Gas Law
The Ideal Gas Law—Molar Mass and Density
Molar mass and the ideal gas law

24. The Ideal Gas Law—Molar Mass and Density (cont.)
SECTION13.2
The Ideal Gas Law
The Ideal Gas Law—Molar Mass and Density (cont.)
Density and the ideal gas law

25. Real Versus Ideal Gases
SECTION13.2
The Ideal Gas Law
Real Versus Ideal Gases
Ideal gases follow the assumptions of the kinetic-molecular theory.
Characteristics of ideal gases:
There are no intermolecular attractive or repulsive forces between particles or with their containers.
The particles are in constant random motion.
Collisions are perfectly elastic.
No gas is truly ideal, but most behave as ideal gases at a wide range of temperatures and pressures.

26. Real Versus Ideal Gases (cont.)
SECTION13.2
The Ideal Gas Law
Real Versus Ideal Gases (cont.)
Real gases deviate most from ideal gases at high pressures and low temperatures.
Polar molecules have larger attractive forces between particles.
Polar gases do not behave as ideal gases.
Large nonpolar gas particles occupy more space and deviate more from ideal gases.

27. SECTION13.2
Section Check
Which of the following is NOT one of the related physical properties described in the ideal gas law?
A. pressure
B. volume
C. density
D. temperature

28. 3.00 mol of O2 at STP occupies how much volume?
SECTION13.2
Section Check
3.00 mol of O2 at STP occupies how much volume?
A L
B L
C L
D L

30. SECTION13.3
Gas Stoichiometry
Determine volume ratios for gaseous reactants and products by using coefficients from chemical equations.
Apply gas laws to calculate amounts of gaseous reactants and products in a chemical reaction.
coefficient: the number written in front of a reactant or product in a chemical equation, which tells the smallest number of particles of the substance involved in the reaction
When gases react, the coefficients in the balanced chemical equation represent both molar amounts and relative volumes.

31. Stoichiometry of Reactions Involving Gases
SECTION13.3
Gas Stoichiometry
Stoichiometry of Reactions Involving Gases
The gas laws can be applied to calculate the stoichiometry of reactions in which gases are reactants or products.
2H2(g) + O2(g) → 2H2O(g)
2 mol H2 reacts with 1 mol O2 to produce 2 mol water vapor.

32. Stoichiometry and Volume-Volume Problems
SECTION13.3
Gas Stoichiometry
Stoichiometry and Volume-Volume Problems
Coefficients in a balanced equation represent volume ratios for gases.

33. Stoichiometry and Volume-Mass Problems
SECTION13.3
Gas Stoichiometry
Stoichiometry and Volume-Mass Problems
A balanced chemical equation allows you to find ratios for only moles and gas volumes, not for masses.
All masses given must be converted to moles or volumes before being used as part of a ratio.

34. SECTION13.3
Section Check
How many mol of hydrogen gas are required to react with 1.50 mol oxygen gas in the following reaction?
2H2(g) + O2(g) → 2H2O(g)
A. 1.00
B. 2.00
C. 3.00
D. 4.00

35. SECTION13.3
Section Check
How many liters of hydrogen gas are required to react with 3.25 liters of oxygen gas in the following reaction?
2H2(g) + O2(g) → 2H2O(g)
A. 2.00
B. 3.25
C. 4.00
D. 6.50

37. Gases Chemistry Online Study Guide Chapter Assessment
Resources
Chemistry Online
Study Guide
Chapter Assessment
Standardized Test Practice

38. The Gas Laws Key Concepts
SECTION13.1
The Gas Laws
Study Guide
Key Concepts
Boyle’s law states that the volume of a fixed amount of gas is inversely proportional to its pressure at constant temperature.
P1V1 = P2V2
Charles’s law states that the volume of a fixed amount of gas is directly proportional to its kelvin temperature at constant pressure.

39. The Gas Laws Key Concepts
SECTION13.1
The Gas Laws
Study Guide
Key Concepts
Gay-Lussac’s law states that the pressure of a fixed amount of gas is directly proportional to its kelvin temperature at constant volume.
The combined gas law relates pressure, temperature, and volume in a single statement.

40. The Ideal Gas Law Key Concepts
SECTION13.2
The Ideal Gas Law
Study Guide
Key Concepts
Avogadro’s principle states that equal volumes of gases at the same pressure and temperature contain equal numbers of particles.
The ideal gas law relates the amount of a gas present to its pressure, temperature, and volume PV = nRT

41. The Ideal Gas Law Key Concepts
SECTION13.2
The Ideal Gas Law
Study Guide
Key Concepts
The ideal gas law can be used to find molar mass if the mass of the gas is known, or the density of the gas if its molar mass is known.
At very high pressures and very low temperatures, real gases behave differently than ideal gases.

42. Gas Stoichiometry Key Concepts
SECTION13.3
Gas Stoichiometry
Study Guide
Key Concepts
The coefficients in a balanced chemical equation specify volume ratios for gaseous reactants and products.
The gas laws can be used along with balanced chemical equations to calculate the amount of a gaseous reactant or product in a reaction.

43. Gases What does the combined gas law relate?
CHAPTER13
Gases
Chapter Assessment
What does the combined gas law relate?
A. pressure and temperature
B. volume and pressure
C. pressure, temperature, and volume
D. pressure, temperature, volume, and amount

44. CHAPTER13
Gases
Chapter Assessment
According to Charles’s law, if pressure and amount of a gas are fixed, what will happen as temperature is increased?
A. Volume will decrease.
B. Volume will increase.
C. Mass will increase.
D. Mass will decrease.

45. CHAPTER13
Gases
Chapter Assessment
Equal volumes of gases at the same temperature and pressure contain equal numbers of particles is stated by:
A. Law of conservation of mass
B. Boyle’s law
C. Avogadro’s principle
D. Ideal gas law

46. CHAPTER13
Gases
Chapter Assessment
What is the volume of 1.00 mol of chlorine gas at standard temperature and pressure?
A L
B L
C L
D L

47. Gases When do real gases behave differently than ideal gases?
CHAPTER13
Gases
Chapter Assessment
When do real gases behave differently than ideal gases?
A. high temperature or low pressure
B. high temperature or high pressure
C. low temperature or low pressure
D. low temperature or high pressure

48. CHAPTER13
Gases
Standardized Test Practice
If two variables are directly proportional, what happens to the value of one as the other decreases?
A. increases
B. decreases
C. remains constant
D. none of the above

49. Gases What conditions represent standard temperature and pressure?
CHAPTER13
Gases
Standardized Test Practice
What conditions represent standard temperature and pressure?
A. 0.00°C and 0.00atm
B. 1.00°C and 1.00atm
C. 0.00°F and 1.00atm
D. 0.00°C and 1.00atm

50. Gases One mole of gas occupies how much volume at STP? A. 1.00 L
CHAPTER13
Gases
Standardized Test Practice
One mole of gas occupies how much volume at STP?
A L
B L
C L
D L

51. Gases Which of the following would deviate the most from an ideal gas?
CHAPTER13
Gases
Standardized Test Practice
Which of the following would deviate the most from an ideal gas?
A. gas in a hot-air balloon
B. water vapor from the reaction of gaseous hydrogen and oxygen
C. upper atmospheric gases
D. gases near absolute zero

52. Gases What volume will 3.50 mol of Xe gas occupy at STP? A. 78.4 L
CHAPTER13
Gases
Standardized Test Practice
What volume will 3.50 mol of Xe gas occupy at STP?
A L
B L
C L
D L

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