AP Chemistry Unit 3 Gas Laws

AP Chemistry Learning Objectives

The student can:

  • 1.17 The student is able to express the law of conservation of mass quantitatively and qualitatively using symbolic representations and particulate drawings.
  • 2.4 The student is able to use KMT and concepts of intermolecular forces to make predictions about the macroscopic properties of gases,  including both ideal and nonideal behaviors.
  • 2.5 The student is able to refine multiple representations  of a sample of matter in the gas phase to accurately represent the effect of changes in macroscopic properties on the sample
  • 2.6 The student can apply mathematical relationships or estimation to determine macroscopic variables for ideal gases.
  • 2.12 The student can qualitatively analyze data regarding real gases to identify deviations from ideal behavior and relate these to molecular interactions.

Unit Essential Questions

  • How are the properties of gases measured and described?
  • What are the mathematical relationships among the quantities used to describe gases?


  • a theory attempts to explain a body of observations
  • The relationship between Celsius and Kelvin temperature scales and why Kelvin temperatures are used to describe gases
  • gases may be described by the volume, pressure, temperature, and number of particles in a particular sample
  • Gases may be described by the ideal gas law, because deviations from this behavior are generally negligibly small

Prior Knowledge

  • symbols and charges of common monatomic ions (see list) predicted from their position on the periodic table
  • common polyatomic ions (see list)
  • chemical nomenclature - ionic and covalent compounds
  • reaction prediction for reactions involving gases
  • stoichiometry and mole-mole ratios
  • units of measurement for volume, mass, moles, pressure. temperature

Prior Skills

  • writing chemical formulas for ionic and molecular compounds
  • writing and balancing chemical equations to describe reactions
  • finding stoichiometric relationships in chemical reactions
  • rearranging simple algebrain equations to solve for each variable
Learning Targets Ch. 5.1 Substances that Exist as Gases

Students will know....

  • the difference between the Kelvin temperature scale and the Celsius scale.
  • the difference between the terms gas and vapor
  • the terms velocity, acceleration, force, newton, energy, joule, kinetic energy,   pressure and pascal.

Students will be able to....

  • List at least ten common substances that exist as gases at 1 atmosphere (atm) pressure and 25oC.
  • List four physical characteristics of all gases.
Learning Targets Ch. 5.2 Pressure of a Gas Problems 5.13, 5.14

Students will know....

  • units of measurement for pressure in a gas
  • equalities relating these units of measurement and how to make conversion factors of them

Students will be able to....

  • Convert between torr, mmHg, atmospheres, and pascals.
  • State the difference between open-tube manometers and closed-tube manometers and explain how each is used.
Learning Targets Ch. 5.3 The Gas Laws Problems 5.17-5.26

Students will know....

  • Write, explain, and apply each of the following:
  • Boyle’s law (P µ 1/ V and P1V1 = P2V2).
  • Charles’s law (P µ T and V1/ T1 = V2/ T2).
  • Avogadro’s law (V µ n).

Students will be able to....

  • measure temperature with the Celsius scale and convert it to Kelvin
  • State laws as useful equations and apply them to real and hypothesized scenarios involving gases
  • Explain the laws desriptively and by using particle models
Learning Targets Ch. 5.4 The Ideal Gas Equation RQ 5.29, 5.30; Problems 5.32, 5.34, 5.35, 5.36, 5.37, 5.38, 5.48-5.52

Students will know....

  • Ideal gas law (PV = nRT)
  • standard temperature and pressure (STP) and demonstrate that at STP one mole of gas occupies 22.4 liters.

Students will be able to....

  • Explain the derivation of the gas constant (R).
  • Use the Ideal gas equation, determine the moles of a gas from measurements
  • Use density, the Ideal gas equation and molar mass to .
Learning Targets Ch. 5.5 Gas Stoichiometry Problems 5.53-5.64

Students will know....

  • that due to Avogadro's law, mole ratios in chemical equations for gases are also volume ratios

Students will be able to....

  • use Avogadro's law in stoichiometric problems involving gases
  • use the Ideal Gas Law in stoichiometric problems involving gases
Learning Targets Ch. 5.6 Dalton's Law of Partial Pressures Problems 5.56-5.76

Students will know....

  • Dalton’s law of partial pressure.
  • the relationship of pressure and moles in a sample of gas: mole fraction
  • that mole fraction is useful with gases having low reactivity

Students will be able to....

  • State Dalton’s law of partial pressures and utilize it in problems involving mixtures of gases including the collection of gases over water.
  • Calculate the mole fraction for each gas in a mixture and use the mole fraction to calculate partial pressures of gases.
  • Define mole fraction and verify that Pa = XaPtotal.
Learning Targets Ch. 5.7 The Kinetic Molecular Theory of Gases (Exploring Properties of Gases Lab)

Students will know....

  • Explain the four assumptions upon which the kinetic molecular theory of gases is based.
  • State how the kinetic molecular theory of gases qualitatively explains the following properties:
    • compressibility
    • diffusion
    • low density
  • Describe the process of gaseous diffusion.

Students will be able to....

  • Explain how a real gas, behaving non-ideally, differs from an ideal gas as described by the four assumptions in the kinetic molecular theory of gases.
  • Describe conditions under which a real gas will approximate an ideal gas.
  • Perform calculations using root-mean-square speeds.
Learning Targets Ch. 5.8 Deviation from Ideal Behavior Additional Problems TBA

Students will know....

  • the conditions under which gases do not behave as ideal gases

Students will be able to....

  • Apply van der Waal’s equation to real gases.
Daily Learning Activities

Day 15 October 20 & 24

Gas Laws - Intro

  • Read The Kinetic Theory together in class; discuss the meaning of the term theory in science.
  • Read Properties of Gases with a focus on the variables and units of measure used in describing quantities of gases. Do a few examples of conversion factors.
  • Particle models of gases - model the models
  • Background and preparation for Gas Law Inquiry Lab

Day 16 October 25 & 26

Gas Law Inquiry Lab

Assignment 2 (due Oct 31/Nov 1) Be sure to be deliberate with your answers, paying close attention to what you are asked to do.

Day 17 October 27 & 28

Discussion of Chapter 5 Directed Reading Part 1 (5.1-5.4) and its relationship to the lab
  • Math details, particle models, and graphs

Prep for Gasometric Analysis lab

  • Dalton's Law of Partial Pressures and collecting a gas over water
  • Gas stoichiometry: applications of Avogadro's principle and V = nRT

Day 18 October 31 & November 1

Gasometric Analysis lab data collection

  • Assignment 2 due
  • Gas Law Lab due - analysis
Day 19 November 2 & 3
  • Gas law stoichiometry and the last part of the guided reading handout
  • Practice scenarios and problem-solving
Day 20 November 4 & 7
  • Assignment 3 due
  • Gasometric Analysis Lab due

Day 21 November 8 & 9

  • Gas Laws Quiz
  • Prepare for Thermochemistry unit directed reading and intro

Links and Resources

Bozeman Science gas laws




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