Question

An ideal gas at room temperature has 105 molecules per cubic centimetre. Its pressure is of the order of

(a) 10-15 atm

(b) 10-10 atm

(c) 10-5 atm

(d) 1 atm

Answer 1

Correct Answer is (a) 10-15 atm

p = nkT = (105 x 106 m-3) (1.38 x 10-23 J K-1) (300 K)

≃10-10 N m-2 = 10-10 pa ≃ 10-15 atm.