[HelpME]

Hey guys,

I'm trying attempt this problem as I'm studying for my mcats, Im really confused by it. Can anyway help me. I havent taken chemistry in a very long time.

As a citizen chemist, you possess the tools to evaluate certain aspects of this issue and become somewhat self-informed. Consider the following question:

What would be the effect on the concentration of atmospheric CO2 in 1 year if 1 billion (1x109)   cars each burned 1000 gal of gas during that year? (Note: There is a current concentration of atmospheric CO2. We want to figure out what the concentration would become after the billion cars ran for that year?)

-   Assume that gasoline is octane (C8H18)
-   Assume that the earth is a smooth sphere with a radius of 4000 miles
-   Atmospheric pressure is 14.7 lbs/in2 , i.e. the weight of the atmosphere is 14.7 lbs on every square inch of the earth
-   The area of a sphere = 4 *  * (radius)2
-   1 lb = 454 grams
-   1 gallon = 4 qts
-   1 qt = ~1.1 L
-   The density of octane is ~0.7 g/mL
-   The current concentration of atmospheric CO2 is 400 ppm (parts per million)
-   1 ppm = 0.0001%


This next question.. i find a bit werid and have no clue how to even start.

There are ~6 billion people and 4 billion domesticated ruminants on the planet. The average ruminant emits ~70L day of CH4 while the average person emits ~3L day of CH4. Calculate the impact of people and domesticated ruminants on the annual increase in CH4 expressed as a % increase of equivalent CO2 to the atmosphere.

[BFGuru]

Please tell me these aren't actual MCAT questions or I may just crumble.