Manometric gas:
A manometric gas is a gas that is used in a manometer to measure pressure. A manometer is a device used to measure the pressure of a gas or a fluid. A common type of manometer is the U-tube manometer, which consists of a U-shaped tube filled with a liquid. When pressure is applied to one end of the tube, the liquid level in the tube changes, allowing the pressure to be measured.
Diatomic gas:
A diatomic gas is a gas composed of two atoms of the same element, such as hydrogen (H2) or nitrogen (N2). These gases are important in many areas of physics and chemistry, including thermodynamics, combustion, and atmospheric science.
Specific heat at constant pressure (Cp) and constant volume (Cv):
The specific heat of a substance is the amount of heat required to raise the temperature of a unit of the substance by one degree Celsius. The molar specific heat of a gas at constant pressure (Cp) is the amount of heat required to raise the temperature of one mole of the gas by one degree Celsius at constant pressure. The molar specific heat of a gas at constant volume (Cv) is the amount of heat required to raise the temperature of one mole of the gas by one degree Celsius at constant volume.
Gas constant (R):
The gas constant (R) is a physical constant that appears in the equation of state of a gas. The equation of state describes the relationship between the pressure, volume, and temperature of a gas. The gas constant is used to relate the specific heat of a gas at constant pressure (Cp) and the specific heat of a gas at constant volume (Cv).
Relation between Cp, Cv, and R:
The relation between the molar specific heat at constant pressure (Cp), the molar specific heat at constant volume (Cv), and the gas constant (R) can be expressed as:
Cp - Cv = R.
Heat capacity ratio (γ):
The heat capacity ratio (γ) is the ratio of the molar specific heat at constant pressure (Cp) to the molar specific heat at constant volume (Cv). It is also known as the adiabatic index. The heat capacity ratio of a diatomic gas is approximately 1.4. The heat capacity ratio of a monatomic gas is approximately 5/3.