CO_2 outgasses through volcanoes and mid-oceanic vents on Earth at a rate of ~ 2
ID: 105334 • Letter: C
Question
CO_2 outgasses through volcanoes and mid-oceanic vents on Earth at a rate of ~ 2 times 10^-4 kg m^-2 of carbon per year. If this outgassed CO_2 accumulated in the atmosphere over 4 billion years, what would be the resulting surface pressure of CO_2 measured in bars? [Caution: l gave the outgassing rate for carbon, but asked for the pressure from carbon dioxide. When finding your solution, be sure to compute the mass of carbon dioxide added to the atmosphere, assuming an appropriate amount of oxygen is added to the atmosphere with the carbon.] b. The actual mass of carbon in today's atmosphere is ~7.5 times 10^14 kg. Let's assume all of this came from the outgassing processes identified in part (a). What fraction of the carbon that has ever been released from outgassing is currently in the atmosphere? c. What important assumptions did we make in part (b)?Explanation / Answer
a.The amount of carbon dioxide released is equal to 2×10^-4kg m-2
The amount of oxygen relaesd in the atmosphere is considered to be =1×10^4kg m-2
The amount of carbon released is =1.5×10^-4 kg m-2
The amount of oxygen and carbon is also considered as they both together make up the carbondioxide particles.
The total amount of particles=2+1+1.5(×10^-4)=4.5×10^-4kg m-2
Converting it into bars,we get=4.5×10^-4×1.0325=4.646×10^-4 bar
b.Mass of carbon=7.5×10^14
The amount of carbon released=(7.5×10^14)/(2×10^-4)=3.75×10^18
c.The important assumptions made are the amount of carbon released and the mass are taken into account and these data are used to identify the appropriate fraction.