Atmospheric Science and Gas Laws: Key Concepts

States of Matter and the Kinetic Molecular Theory

• Brownian motion: The random movement of microscopic particles suspended in a liquid or gas.
• Kinetic Molecular Theory: The idea that all substances are composed of entities that are in constant, random motion.
• Kinetic energy: Energy possessed by moving objects.
• Temperature: A measure of the average kinetic energy of the entities of a substance.

The Atmosphere and Its Components

• Greenhouse effect: A natural process whereby gases and clouds absorb infrared radiation emitted from Earth’s surface and radiate it, heating the atmosphere and Earth’s surface.
• Carbon sequestration: The process of removing carbon dioxide and other forms of carbon from the atmosphere, and then storing it.

Air Quality

• Photochemical smog: A hazy cloud of air pollutants formed by the reaction of emissions from factories and vehicles with sunlight.
• Particulate matter: The mixture of very small solid and liquid particles found in the atmosphere.
• Air Quality Health Index (AQHI): A numerical scale used to indicate overall air quality based on concentrations of air pollutants including ozone, particulate matter, and nitrogen dioxide.

Indoor Air Quality

• Off-gassing: The release of one or more gases from a substance or product at normal temperatures and pressures.

Atmospheric Pressure

• Atmospheric pressure: The force per unit area exerted by air on all objects.
• Standard pressure: 101.325 kPa (often rounded to 101.3 kPa).
• Standard temperature and pressure (STP): 0°C and 101.325 kPa (exactly).
• Standard ambient temperature and pressure (SATP): 25°C and 100 kPa (exactly).

The Gas Laws – Absolute Temperature and Charles’ Law

• Absolute zero: The theoretical temperature at which the entities of a material contain no kinetic energy and therefore transmit no thermal energy; equal to -273.15°C.
• Kelvin temperature scale: A temperature scale that includes absolute zero and the same-sized unit divisions as the Celsius temperature scale.
• Absolute temperature: A measurement of the average kinetic energy of the entities in a substance; unit symbol K.
• Charles’ law: The statement that as the temperature of a gas is increased, the volume of the gas increases proportionally, provided that the pressure and amount of gas remain constant; the volume and temperature of a gas are directly proportional.

Gas Laws

• Boyle’s law: The statement that as the volume of a gas decreases, the pressure of the gas increases proportionally, provided that the temperature and amount of gas remain constant; the volume and pressure of a gas are inversely proportional.
• Combined gas law: The statement that the product of the pressure and volume of a gas sample is proportional to its absolute temperature in kelvins.