# Stoichiometry



## bubba13 (Jan 6, 2007)

1) In the formation of carbon dioxide from carbon monoxide and oxygen, how many moles of carbon monoxide are needed to react completely with 7.0 moles of oxygen gas?
2 CO + O2 -> 2 CO2


The equation is already balanced - 2C on each side, and 4O. So all you need to do is convert moles. You have 7.0 moles oxygen gas. You need to react it conpletely with the carbon monoxide. According to the formula, it takes 2CO to react with 1O2. So 7.0*2 = 14 moles CO.

2) How many grams of water can be prepared from 5moles of hydrogen at standard conditions?
2 H2 + O2 -> 2 H2O

Again, already balanced. If you have 5 moles of hydrogen gas, you'll get 5 moles of water, because the ration is 2:2 or 1:1. So 5 moles of water equals how many grams of water? Use the periodic table and convert (hint: think the molecular mass of hydrogen and oxygen).

3) Ammonia, NH3, is commercially prepared by the Haber process. How many moles of ammonia can be formed from 44.8 liters of nitrogen gas and an excess of hydrogen at standard conditions?
3 H2 + N2 -> 2 NH3

I think you're going to have to use the gas law for this one. PV=nRT. Have you been given that formula? You know that V = 44.8, and you'll need to find n (moles) using standard conditions, which I'm assuming is atmospheric pressure and all. When you know moles of nitrogen gas, multiply by two to find moles of ammonia.


----------



## tempest (Jan 26, 2009)

Bubba, you are my saving grace for the day. I thank you with my all of my heart. Please continue to be a chemistry genius just in case I ever need help in Chemistry again.


----------



## bubba13 (Jan 6, 2007)

Was the last one right? Gas law and all?
Good luck on your homework/test. Curious, what grade are you in?


----------



## tempest (Jan 26, 2009)

I'm a senior, and I think I'll need the luck, along with the rest of my classmates because apparently I'm not the only one who couldn't figure these problems out. 
And I'm not sure if the last one is right, which is why I'm just going to have to wing it. The fact that my classmates are having the same amount of trouble that I am means that we may just spend more time learning with this. Which it's apparent that we need. I'm hoping I know enough to at least be able to find decent answers. We should've asked our teacher to explain more. But I honestly thought I understood it.


----------

