Question

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

Answer 1

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`