characteristic constants of gases

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gas density (table 35)

If M is the mass of a litre at 0°C, the mass of the litre at t °C for the same pressure is :

M’ is the mass of a litre at 101.3 kPa, the mass of the litre at the real pressure is :

solubility of the main gases in water (table 36, figures 30, 31, and 32)

The following formula is used to find the amount of gas dissolved in a liquid from the Henry constant (figure 30) :

P = total gas pressure.

H = Henry constant expressed in the same unit as P.

x_i = molar fraction for the gas in the liquidmolar fraction for the gas in the liquid.

y_i= molar fraction for the gas in the gaseous mixture.

kinematic viscosity of common gases

The kinematic viscosity n based on temperature, at the normal pressure of 101.3 kPa is given in m²·s^–1 in table 37.

This viscosity needs to be corrected based on pressure according to the following relation (not applicable for water vapour) :

where:

' = corrected kinematic viscosity, in m²·s^–1,

P' = true absolute pressure,

P = normal absolute pressure, expressed in the same unit as P'.

The density ρ' of the fluid, in kg · m^–3 under temperature conditions t’ (°C) and absolute flow pressure P’ can be calculated from density r under normal conditions using the following equation :

absolute humidity of atmospheric air at saturation versus the dew point

chlorine

general characteristics

In its normal state, chlorine is a greenish-yellow gas; its physical constants are described in section the oxidants and disinfectants.

At 15°C and under a 101.3 kPa pressure, 1 kg of chlorine generates 314 litres of chlorine gas and 1 litre of liquid chlorine which is equal to 456 litres of gas. The gas is liquefied by cooling and by compression at a pressure that varies with temperature: 1 000 kPa at 40 °C; 500 kPa at 18 °C.

the influence of temperature and pressure

Chlorine is a gas that irritates and suffocates; it is not corrosive in its pure and dry form. Nevertheless, it is extremely corrosive in the presence of humidity, however little. It has the following characteristics: high reactivity with most simple compounds and likely to create explosive reactions with ammonia, hydrogen…