The Earth's atmosphere is a mixture of gases such as nitrogen
CHEMISTRY · Single correct · A Level · Chemistry · Amount of substance · Amount of substance
Problem
The Earth's atmosphere is a mixture of gases such as nitrogen, oxygen, tiny amounts of carbon dioxide and traces of other gases. Because of the pull of gravity, these gases tend to accumulate near the surface of the Earth. The weight of these gases causes an atmospheric pressure of about 105 Pa on the surface of the Earth. Because the density of air decreases with height (h above the surface of the Earth), the atmospheric pressure (P) decreases with h. In fact P varies with h as P=P0e−h/h0 where P0 = atmospheric pressure at sea level (h=0) and h0 is a constant.
The pressure gradient, dP/dh is proportional to ρn where ρ is the density of air. The value of n (using ideal gas approximation) is :
(A) zero
(B) 21
(C) 1
(D) 2