Question

In the Updated Climate Change PPT/video numbers were cited for the worldwide emissions of carbon dioxide in Gigatons (=10¹⁵g) and the annual increase in the atmospheric concentration of the gas in ppm. Data was also given on the percentage of emitted gas that remains in the atmosphere and is not absorbed by plants or the ocean. If annual emissions are 36 Gigatons and the annual increase in concentration is 2.36 ppm, what percent of the carbon dioxide has remained in the atmosphere? Note that the actual process is more complex than this implies, including the fact that there is a time lag involved, but the results of your calculation are reasonable, which you can confirm by the value given in the slide for the percent retained in the atmosphere. For the calculation you will need to know that the mass of atmosphere of the Earth is about 5.1 x 10²¹ g. The standard assumption is that the molar mass of air is 29.0 g/mol (intermediate to the 28 of N₂ and 32 for O₂, but closer to the former given its higher concentration).

This is a hint on the process: Find the total number of mols of air that are in the atmosphere and use the concentration of CO₂ in ppm to get the mols of CO₂.and then the increased grams of the gas. Compare this to the grams of CO₂ released to determine the percent which remains. Keep extra digits and do not put the percent sign in your answer.

Answer 1

Solution:

The moles of air in earth's atmosphere are calculated as below,

Mass of earth = 5.1*10²¹ gm

Molar mass of air = 29 g/mol

Hence molar mass of air is,

The concentration of carbon dioxide in ppm is converted to moles,

2.36 ppm = 2.36*0.001 g =0.00236 gm

moles of emission with annual increase is 0.000107 moles

% of CO₂ emission in air = (0.000107/0.0000536)*100 = 200%

So the pollution (or) in simple emission rate is doubling with an annual increase which is quite unsafe for the environment.