One mole of any gas will occupy 22.4 L and contain ________ molecules.

(Answer to Q. 1)  ANS: A
1 mole of oxygen (mw = 32 g) occupies a volume of 22.4 L and contains 6.02  1023 molecules when measured at 0 C (273 K) and 1 atm.

(Answer to Q. 2)  ANS: C
Diffusion is movement of molecules from areas of high concentrations to low concentrations. Effusion refers to the seepage or loss of blood through torn blood vessels. Osmosis describes the movement of water across a semipermeable membrane from a less-concentrated to a more-concentrated area. Suspensions are mixtures of solutions with undissolved particles or mol-ecules.

(Answer to Q. 3)  ANS: A
Partial pressure of oxygen =  oxygen  barometric pressure, or 0.25  760 mm Hg = 190 mm Hg.

(Answer to Q. 4)  ANS: B
The partial pressure of nitrogen can be calculated by multiplying the barometric pressure by the percentage of nitrogen in the air, or 760 mm Hg  0.78 = 592.8 mm Hg.

TYVM

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