Ho much co2 is in humen breath?

Answer 1

average adult breathes about 0.5 L of air per breath at rest. Normal air contains ~ 0.03 % of CO2 which gets enriched to 4 % of exhaled air. The difference, 3.97 % is what you exhaled. One mole of air at room temperature have a volume of ~22.4 L (use ideal gas equation p*V=n*R*T, p=pressure [bar], V=volume, n=amount in mole, R=ideal gas constant, T=temperature [Kelvin]). 1 mole CO2 is equivalent to 44 g.

So, 0.5 L*(1 mole /22.4 L)*(44 g / mole) = 0.982 g

One breath therefore contains ~ 1 g of exhaled CO2

Note: Some of the gases are not ideal (mostly CO2), the volume of one breath depends on the person (sex, age, fitness, size) and the activity. It can be up to 2 L at least. But it is just an approximation anyways.

Btw - 1 kWh of electricity cost about 600 g of CO2. An average light bulb of 60 W therefore gives rise to the production of 10 g CO2 / s during use (not counting its production or disposal).