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=nRTPVn=RTVn=RTP=Vmolar

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:

V1mole=0.082LatmmolK273.15K1.00atm=22.4Lmol=Vmolar

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:

Vn=22.4LmolV=n22.4Lmol - this means that the more moles of o substance you have, the bigger its volume will be at STP. Since we have

200.0g1moleCO28.0g=7.14 moles, the volume occupied will be V=7.14moles22.4Lmol=160.0L