What is the molar volume of 200.0 grams of carbon monoxide??

1 Answer
Dec 28, 2014

Molar volume problems must contain some information about pressure and temperature, that is the only way a value for a substance's molar volume can be determined. Here's how that works:

Starting from the ideal gas law, #PV = nRT#, let's try and find an expression for molar volume

#pV = nRT -> (PV)/n = RT -> V/n = (RT)/P = V_(molar)#

So, a gas' molar volume depends on temperature and pressure. Let's assume that we are at 273.15 K and 1.00 atm, and we want to determine what volume 1 mole of a gas occupies:

#V/(1 mol e) = (0.082 (L * atm)/(mol * K) * 273.15K)/(1.00atm) = 22.4L/(mol) = V_(molar)#

This represents the volume 1 mole of any ideal gas occupies at STP - Standard Temperature and Pressure (273.15 K, 1.00 atm).

Let's try and determine the molar volume of #200.0g# of #CO# at STP:

#V/n = 22.4L/(mol) -> V = n * (22.4L)/(mol)# - this means that the more moles of o substance you have, the bigger its volume will be at STP. Since we have

#200.0g * (1 mol e CO)/(28.0g) = 7.14# moles, the volume occupied will be #V = 7.14 mol es* 22.4L/(mol) = 160.0L#