# Homework Help: Negative Electric Charge

1. Oct 13, 2009

### dtrain121

1. The problem statement, all variables and given/known data
Find the negative electric charge of all the electrons in a 56 liter sample of oxygen gas at STP. Assume the oxygen gas is diatomic.

2. Relevant equations

3. The attempt at a solution

2. Oct 13, 2009

### dotman

Hello,

Diatomic, of course, means that each oxygen molecule contains 2 oxygen atoms (ie, O2). Cool. So you know you have 56 liters of a gas, oxygen here, at STP. Do you have a formula that would allow you to calculate how many molecules of O2 gas would occupy that much volume? After you calculate that, its a simple matter of finding out how many electrons each O2 molecule contains, and multiplying your number of molecules by the number of electrons in each molecule by the total charge of each electron.

Hope this helps, reply if you need more clarification! I've deliberately avoided simply giving you the formulas, of course.

3. Oct 13, 2009

### dtrain121

he did not give me any formulas. i would not know where to start. can you please give me the formulas?

4. Oct 13, 2009

### dotman

You need to start by calculating the number of atoms of the gas that are contained in a 56 liter container, at STP-- ie, 1 atmosphere, and 0 degrees C.

No, I will not give you the formula. You should be able to find this one on your own. It's one of the more famous formulas out there. Have you even looked for it? Or thought about where you could?

We're not here to do your work for you.