Unit 9
Chapter Overview
During this unit, the ideal gas laws are taught through experience and then taught conceptually, graphically, and mathematically to give students a broad understanding of kinetic molecular theory and how temperature, pressure, volume, mass, and moles are related. Students then use balanced equations, the gas laws, and molar volume to solve gas stoichiometry problems.
Main Ideas
Kinetic molecular theory is used to understand and predict the behavior of ideal gases.
There is a relationship between ideal gas pressure and volume (when the temperature and moles remain constant).
There is a relationship between ideal gas volume and temperature (when pressure and moles are held constant).
There is a relationship between pressure, volume, temperature, and the number of moles for an ideal gas.
Boyle, Charles, Gay-Lussac, Dalton, and Avogadro made contributions to our current understanding of gas behavior.
There is a relationship between volume and number of moles for an ideal gas (when pressure and temperature are held constant).
Avogadro’s law and the ideal gas laws can be applied to chemical stoichiometry to determine mass, pressure, volume, temperature, and mole relationships in chemical reactions involving gases.
There is a relationship between the total pressure of a mixture of gases and the pressures of the component gases.
Misconceptions
Students may think gases do not have mass.
Students may think air and oxygen are the same gas ions.
Students may not understand how to use dimensional analysis.
Students may not understand significant figures.
Vocabulary
Ideal Gas Laws – mathematical formulas that describe the relationships among temperature, pressure, volume, and moles in ideal gases
Ideal Gas – a hypothetical gas whose molecules occupy negligible space and have no interactions, and that obey gas laws exactly
Boyle’s Law – the pressure and volume of a gas have an inverse relationship when temperature is held constant
Charles’ Law – the volume of an ideal gas at constant pressure is directly proportional to the absolute temperature
Avogadro’s Law – equal volumes of all gases at the same temperature and pressure contain equal number of molecules
Dalton’s Law of Partial Pressure – in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases
Standard Temperature and Pressure (STP) – the standard temperature is 273°K, 0°C, or 32°F and the standard pressure is 1atm
Gas Stoichiometry – the relationship between the reactants and products in chemical reactions that produce gases
Kinetic Molecular Theory - a theory of the thermodynamic behavior of matter, based on the dependence of temperature on the kinetic energy of the rapidly moving particles of a substance
Notes
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