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## Homework Statement

The total mass of C contained in all fossil fuels burned from 1750 to 2000 is estimated

as 2.77 x 1014 kg C. The amount of C released as CO2 from agricultural expansion and

deforestation during the same period is estimated as 1.31 x 1014 kg C. The concentration

of CO2 in the atmosphere was 360 ppm in 2000, corresponding to an atmospheric pool

mass of C of 7.74 x 1014 kg C. If the concentration of CO2 in 1750 was 280 ppm,

calculate the % of C from these 2 sources that has stayed in the atmosphere over the 250

years.

## Homework Equations

Shown in class how to calculate molecular mass of atmosphere, was 28.96 g/mol

## The Attempt at a Solution

I tried calculating molecular mass of atmosphere which is 28.96 g/mol.

Took 360 ppm = 360E-6 multiplied it by 44 g/mol CO2.

I got 0.01584 g/mol then divided this by molecular mass of atmosphere so CO2 is 0.05469%. I'm stuck and don't know how to relate this percent to mass of carbon.

I have also been suggested to use it a proportion so if 7.74E14 kg relates to 360 then 280 ppm CO2 relates to 6.02E14 Kg Carbon, but this doesn't seem right to me.

I just need to understand how ppm CO2 relates to kg C I think