The Determination of Molar Mass of Gases and Volatile Liquids Classic Lab Kit for AP* Chemistry teaches students to compare the molar mass of specific gases by comparing masses of equal volumes of gases at the same temperature and pressure.
Classic AP Requirement #3—Determination of the Molar Mass by Vapor Density
The molar masses of specific gases are found by comparing masses of equal volumes of gases at the same temperature and pressure. Oxygen gas is selected as a standard, and molar masses are assigned from it. In Part 2, the molar masses of specific volatile liquids are determined in a microscale experiment and by use of the Ideal Gas Law. Students gain experience in handling gases, using the analytical balance and in microscale chemistry procedures.
Complete for 24 students working in pairs.
Determination of the Molar Mass: Gases & Volatile Liquids Inquiry Guidance and AP* Chemistry Curriculum Alignment Transition Guide available! Follow the link in Resources to find this valuable publication that lets you adapt this classic AP Chemistry experiment for guided-inquiry and correlate with the AP Chemistry curriculum framework.
Correlation to Next Generation Science Standards (NGSS)
Science & Engineering Practices
Asking questions and defining problems Developing and using models Planning and carrying out investigations Analyzing and interpreting data Using mathematics and computational thinking Engaging in argument from evidence Obtaining, evaluation, and communicating information
Disciplinary Core Ideas
HS-PS1.A: Structure and Properties of Matter
Crosscutting Concepts
Patterns Cause and effect Scale, proportion, and quantity Systems and system models Energy and matter
Performance Expectations
HS-PS1-7. Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.
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Molar Mass: Gases & Volatile Liquids Inquiry Guidance/AP* Chem Curriculum Alignment Transition Guide