Density of Air

Given that it is 21% Oxygen and 79% Nitrogen by mass.

Oxygen: Atomic number is 8, Atomic mass is 16, and molecular mass is 32 (diatomic).

In 100g of air 21g is Oxygen occupying 21x22.4/32 litres at STP=14.7 litres.

Nitrogen: Atomic number 7, atomic mass is 14 and molecular mass is 28.

In 100g of air 79g is Nitrogen occupying 79x22.4/28 litres=63.2 litres.

So for air 100g occupies 77.9 litres. Density= 100g/77.9 litres=1.2837g/l or 1.2837kg/m^3

alternatively

density of oxygen=32/22.4 g/l =1.4286g/l

density of nitrogen=28/22.4 g/l =1.25g/l

density of air= 0.21x1.4286+0.79x1.25=1.2875kg/m^3

simples

Assignment 1: Combustion

You will find three video clips below. Download and watch them as they provide the opportunity to evidence a merit grade.

And also a bit about flue gas analysis

Second section of the unit is available for download here. Fluids

ADDITIONAL INFORMATION ABOUT CENTRE OF PRESSURE here

INFORMATION ABOUT THERMODYNAMIC BASICS here