BIOL 1119 Lecture 20: AP Class 18
Document Summary
Air consists of about 79% nitrogen, about 21% oxygen, and very small amounts of water vapor, carbon dioxide and minor gases. Da(cid:731)(cid:739)(cid:734)(cid:733)"(cid:738) (cid:731)a(cid:742): t(cid:734)(cid:739)a(cid:731) a(cid:739)(cid:732)(cid:734)(cid:738)(cid:735)(cid:727)(cid:724)(cid:737)(cid:728)c (cid:735)(cid:737)(cid:724)(cid:738)(cid:738)(cid:740)(cid:737)(cid:724) (cid:728)(cid:738) a (cid:738)(cid:740)(cid:732) (cid:734)(cid:725) (cid:739)(cid:727)(cid:724) contributions of each gas in the mixture. Pressure of each gas exerts is independent of the pressure the other gases each exert. The separate contribution of each gas is called its partial pressure, which is symbolized by p followed by the gas formula. (ex. Pn2 nitrogen: (cid:699)a(cid:738) a"(cid:738) % (cid:734)(cid:725) (cid:739)(cid:734)(cid:739)a(cid:731) (cid:732)(cid:734)(cid:731)(cid:724)(cid:738) = (cid:726)a(cid:738) a"(cid:738) % (cid:734)(cid:725) (cid:739)(cid:734)(cid:739)a(cid:731) (cid:735)(cid:737)(cid:724)(cid:738)(cid:738)(cid:740)(cid:737)(cid:724) If sea level pressure is 760 mmhg and nitrogen is 78. 6% of air: pn2 = . 786 x. 760 mmhg = 597 mm hg or 78. 6% of total pressure. The partial pressure of a gas is proportional to its concentration. The partial pressure of a gas in a mixture is the fractional concentration of the gas times the total pressure of all gasses.