What is the weigh of air and the wieght C02 per litre of gas or the specific wieght?

Answer 1

At level of sea (about 101.3 KPa) and 20°C, the density of air is aprox. 1.2 Kg/m³

The dry air contains 0.0381% (V/V) of CO2. As you ask the weight per litre, we have to know the density of the CO2:

dens (CO2 gas) = 1.98 kg/m³ = 0.00198 Kg/L, it means that specific weight is equal to:

sp. weight CO2 in air = (0.0381 L CO2 / L air)(0.00198 Kg CO2/ L CO2) =
sp. weight CO2 in air =7.5438 x 10^-5 Kg CO2 / L air
sp. weight CO2 in air = 0.075438 g CO2 / L air

Good luck!

Answer 2

1 mole of any ideal gas occupies 22.4 litres at STP
If you assume ideal behaviour for carbon dioxide, then 1 litre will contain 1/22.4 moles.
Since Formula Mass of CO2 is 44 g per mole, then 1 litre will weigh 44/22.4 = 1.96g approximately.

For air, if you assume that each component behaves ideally then you could work the mass out using ratios or percentages and the same sort of calculation as above.