Gaseous State: Gas Laws
* Volume, number of moles, pressure and temperature are the four interrelated properties that describe the behaviour gases.
* Boyle’s Law describes the relationship between pressure and volume. It states that volume is inversely proportional to pressure at constant temperature and number of moles.
* Charles’ Law describes the relationship between temperature and volume. It states that volume is directly proportional to temperature at constant temperature pressure and number of moles.
* Avogadro’s Law describes the relationship between volume and number of moles. It states at same temperature pressure, equal volume of gases contain equal number of molecules.
Ideal Gas Equation and Absolute Temperature
* Gas thermometers are used to get accurate temperature readings of a body.
* Boyle’s Law: If the temperature of a given mass of gas is constant then its pressure is inversely proportional to its volume.
* Charles’Law: At constant pressure, the volume of a given mass of gas is directly proportional to its temperature, T.
* An Ideal Gas Equation is: nRT
* The relation between the Absolute temperature and Celsius temperature is expressed as: T = tc + 273.15
Gaseous State: Kinetic Molecular Theory
* Kinetic Molecular Theory is a set of five assumptions that describes the behaviour of molecules in gas.
* Gases consist of a very large number of extremely small particles called molecules, which are in constant, continuous, random and straight – line motion.
* The molecules of a gas are separated from each other by great distances. Hence the actual volume of all the molecules of the gas is negligible when compared to the volume occupied by the gas.
* Attractive and repulsive forces between the molecules of a gas are negligible as they are much away from each other.
* Boyle’s Law states that, the volume of a given mass of a gas decreases with increase in pressure at a given temperatures.
* Charles’ law states that at constant pressure, the volume of a given mass of a gas increase with increase in temperature.
* Avogadro’s Law states that equal volumes of all gases under similar conditions of temperature and pressure contain equal number of molecules.