Question

Calculate the number of moles of CO2 that are emitted into the atmosphere per year due to
the total energy consumption on earth (16TW). Note: 1kg oil yields 42MJ and for oil C:H
= 1:2.

Answer 1

So, the total amount of energy consumed per year is: 16 x 10^12 x 60 x 60 x 24 x 365 = 5.05 x 10^14 MJ, which makes the amount of oil used: 5.05 x 1014 / 42 = 1.2 x 1013 KG.

Answer 2

1.2 x 10^13 KG oil

Answer 3

Great. Now write the equation for the combustion process

Answer 4

what is the structural formula of "oil" ?

Answer 5

In reality it's a bunch of hydrocarbons of varying lenghts, but it's given in the question as \(\sf CH_2\)

Answer 6

That's the missing link I was looking for!

Answer 7

2 CH2 + 3 O2 -> 2 H2O + 2 CO2

Answer 8

awesome, do you know how to solve the rest?

Answer 9

Amount of oil used: 5.05 x 10^14 / 42 = 1.2 x 10^13 KG. Molar mass CH2: 14.02g/mol.
Amount of oil used: 1.2 x 10^16 / 14.02 = 8.58 x 10^14 mole CH2
Reaction formula combustion CH2: 2 CH2 + 3 O2 -> 2 H2O + 2 CO2
For every 2 mole CH2 that is burned, 2 mole CO2 is released into the atmosphere.
Number of moles CO2 emitted into the atmosphere = 8.58 x 10^14

Like that?

Answer 10

yup! that's it

good job man

Answer 11

thanks! Now, the next question is:

Calculate the expected increase in CO2 concentration in the atmosphere (in ppm per year),
using your result from question a.

I could use avogadro's number to calculate how many CO2 molecules are emitted, but how would I possibly know what number to divide that against?

Answer 12

ppm just means mg/L, so you could convert the moles to mass

As for the volume, i have no idea. you can probably google it

Answer 13

Ok thx!

Answer 14

np!