A container has a volume of #3 L# and holds #7 mol# of gas. If the container is expanded such that its new volume is #15 L#, how many moles of gas must be injected into the container to maintain a constant temperature and pressure?

1 Answer
Jul 17, 2018

Answer:

28 mol

Explanation:

#PtimesV = ntimesRtimesT#

P is pressure
V is volume
n is mol
R is the universal gas constant
T is temperature.

1st situation:
#Ptimes3=7timesRtimesT#

2nd situation
#Ptimes15=ntimesRtimesT#

P is the same in the 1st and 2nd situations. R and T are the same also (n is the moles in the second situation).

#3/15 = 7/n#

#n=(7times15)/3 = 35# moles (total in the second situation. It means there are #35-7 = 28# moles of gas must be injected to have the condition.