Video Transcript
According to Avogadro’s law, which
of the following are directly proportional to each other at constant temperature and
pressure? (A) Rate of diffusion and molecular
weight. (B) Solubility and pressure. (C) Gas pressure and volume. (D) Gas volume and number of
moles. Or (E) temperature and volume.
Avogadro’s law is just one of
several named laws that can help us to better understand the behavior of a gas. Avogadro’s law specifically deals
with the relationship between the volume of a gas and the number of moles of that
gas. Avogadro’s law states that at
constant temperature and pressure, the volume and number of moles of a gas are
directly proportional. This means that if the number of
moles of a gas are increased, the volume occupied by that gas will also increase at
a constant rate.
We can see Avogadro’s law in action
when we blow up a balloon. When the piston of the air pump is
depressed, more air or more moles of gas are added to the balloon, and the volume of
the balloon increases. So, the volume of a gas is directly
proportional to the number of moles of gas. But this relationship only holds
true at constant temperature and pressure.
So, according to Avogadro’s law,
the two quantities that are directly proportional to each other at constant
temperature and pressure are gas volume and number of moles, or answer choice
(D).
