Increasing the humidity
A)increases the density because humid air feels 'thick'
B)increases the density because winds are usually weaker when the humidity is high
C)decreases the density because humid air usually sinks
D)decreases the density because the molecular weight of water is less than the molecular weight of the other major constituents of air

Question

Quizplus · Accepted Answer

The molecular weight of water (18) is less than the average molecular weight of air (28.96), therefore adding water vapor to the air decreases the overall average molecular weight, and hence decreases the air density.

Increasing the Humidity