[دنـــا]

9. Air contains 78% N2, 21% O2, and 1% Ar, by volume. What is the density of air at 1,000. torr and -10C?

A. 1.0 g/L
B. 6.1 g/L
C. 1.3 g/L
D. 1.8 g/L
E. 0.56 g/L