How can I calculate the volume occupied by 4.4g of co2 at STP?

Expert Answers
mere310ann eNotes educator| Certified Educator

To answer this question, you must use the ideal gas equation:

P V = n R T

"P" stands for pressure, "V" stands for volume, "n" stands for number of moles, "R" stands for gas constant, and "T" stands for temperature.

The problem mentions that this scenario occurs at STP, which stands for standard temperature and pressure. This automatically gives us two important pieces of information: (1) the temperature in the scenario is 273 K & (2) the pressure in the scenario is 1 atm.

It's also given to us that there are 4.4 g of CO2 present in the scenario, which can help us to calculate the number of moles!  By looking at the periodic table, we can see that 1 mole of carbon has a mass of 12.011 g & 1 mole of oxygen has a mass of 15.999 g.  Since 1 mole of CO2 is composed of 1 mole of carbon and 2 moles of oxygen, we can find that 1 mole of CO2 has a mass of 44.009 g.

`(12.011 g) + 2 xx (15.999 g) = 44.009 g` 

We then use the molar mass of CO2 to find the number of moles:

`(4.4 g)/1 xx (1 mol)/(44.009 g) = 0.10 mol`


The gas constant -- "R" -- is a constant, and we choose which ones to use based on the other units in our scenario.  Since this scenario deals with atm, K, and mol, we will use the following for "R":

`R = 0.08206 (L atm)/(mol K)`

Now we can put everything we know into the ideal gas equation & solve for volume:

`(1 atm) xx V = (0.10 mol) xx (0.08206 (L atm)/(mol K)) xx (273 K)`

`V = 2.2 L`