CHEMISTRY Matter and Change Chapter 13: Gases

Table Of Contents Section 13.1 The Gas Laws CHAPTER13 Table Of Contents Section 13.1 The Gas Laws Section 13.2 The Ideal Gas Law Section 13.3 Gas Stoichiometry Click a hyperlink to view the corresponding slides. Exit

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

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.

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

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.

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

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.

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.

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

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.

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

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

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

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

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.

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.

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.

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

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 0.0821 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.

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

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

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

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.

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.

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

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. 30.0 L B. 22.4 L C. 25.4 L D. 67.2 L

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.

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.

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

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.

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

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

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

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.

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.

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

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.

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.

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

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.

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

CHAPTER13 Gases Chapter Assessment What is the volume of 1.00 mol of chlorine gas at standard temperature and pressure? A. 1.00 L B. 18.0 L C. 22.4 L D. 44.8 L

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

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

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

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. 1.00 L B. 2.20 L C. 22.4 L D. 33.7 L

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

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. 78.4 L B. 22.4 L C. 25.9 L D. 54.4 L

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