A container has a volume of #4 L# and holds #3 mol# of gas. If the container is expanded such that its new volume is #36 L#, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

1 Answer
Sep 15, 2016

#27# moles

Explanation:

Let's use Avogadro's law:

#v_1/n_1 = v_2/n_2#

The number 1 represents the initial conditions and the number 2 represents the final conditions.

• Identify your known and unknown variables:

#color(red)("Knowns:"#
#v_1#= 4 L
#v_2#= 3L
#n_1#= 36 mol

#color(blue) ("Unknowns:"#
#n_2#

• Rearrange the equation to solve for the final number of moles:

#n_2=(v_2xxn_1)/v_1#

• Plug in your given values to obtain the final number of moles:

#n_2=(36cancelLxx3mol)/(4\cancel"L")# = # 27 mol#