Question

What is the volume of 3.5 moles of oxygen gas (O2) at standard temperature and pressure (STP)?

6.4 L
22.4 L
32.0 L
78.4 L

Answer 1

The answer can easily be determined with the integrated gas law PV=nRT, where pressure is atm, volume is in liters, n is number of moles, R is 0.0821 (atm*L)/(mol*K), and K is temperature in Kelvin

Answer 2

That is so confusing

Answer 3

Well so let's substitute in the values you need. Hopefully that clarifies things.

Answer 4

You know the pressure is 1 atm, so P=1
You want to find the volume, so V is our variable.
You know there are 3.5 moles of gas, so n=3.5
R is a constant. With the units we are using, it is 0.0821
T is temperature in Kelvin, STP means that the temperature 0 degrees celsius or 273 degrees Kelvin

Answer 5

The integrated gas law is derived from Avogadro's Hypothesis, Gay-Lussac's Law, Boyle's Law, and Charles' Law, which in different ways relate moles, volume, temperature, and pressure.

Answer 6

Does that clear things up a bit?

Answer 7

I think so. If I need any more help I'll come to you. thank you (:

Answer 8

There's another way to do this, actually

Answer 9

If you say that there is one mole of gas at STP, it takes up a space of approximately 22.4 liters. Since pressure is 1, you can just multiply that number by 3.5 to find your final answer.

Answer 10

to the 22.4 liters ?

Answer 11

Right. 3.5*22.4. That's the quick and easy way. The actual method would need PV=nRT, but personally once I knew it was at STP I would just multiplied the 22.4 value, considering you only need one place past the decimal point.

Answer 12

okay (: that makes sense haha. Thanks!

Answer 13

By now I'm sure you've worked it out, and that your final answer should be the final option, or 78.4 L. I hope I've answered your question!

Answer 14

yes (: thanks