Question

What is the density of 1.00 mol of carbon monoxide gas at STP?

Answer 1

Density = mass / volume.

If this is an ideal gas then 1mol will take up 22.4L of volume (fact about ideal gases you should remember)

Since you have 1mol then you know the volume of the gas that you have (22.4L)

Now, just convert 1mol of CO to grams.The ptable tells you that the mass of 1 mol of C is 12g and the mass of 1 mol of O is 16g. So the mass of 1 mol of CO is......... :):)

Now you have the mass and the volume, so just divide :) enjoy