The average atmospheric pressure at sea level is 1013.25 mb, or 14.7 pounds per square inch. using this information, calculate the total mass of the atmosphere. convert your final answer to kilograms. assume that the earth is a sphere and that the elevation of the surface is exactly sea level everywhere. hint: the formula for the surface area of a sphere is s = 4πr2, where r = the radius of the earth = 6370 km. show all work in the space provided below.