Stoichiometry - The Horse Forum
Old 04-23-2011, 08:55 PM Thread Starter
Green Broke

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Stoichiometry

So, I'm down to my last straw in trying to figure out how to do these problems. If you decide to help me I'd prefer that you don't give me the answer, instead actually instruct me on how to reach the answer. I hope someone can help me because I just don't know how to solve the problem and I've tried Google, my Chemistry notes and books, and a little instruction booklet on Chemistry itself. Amazingly, nothing helped. So please help me out. Like I said before, show me the steps to solve the problem, not the answer itself.

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

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

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

Remember, no answers, just steps on how to reach the answers if that's at all possible.

"And somewhere in the northwoods darkness a creature walks upright. And the best advice you may ever get is: Don't go out at night..."
tempest is offline

Old 04-24-2011, 01:10 PM
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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.
bubba13 is offline
Old 04-24-2011, 02:15 PM Thread Starter
Green Broke

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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.

"And somewhere in the northwoods darkness a creature walks upright. And the best advice you may ever get is: Don't go out at night..."
tempest is offline

Old 04-24-2011, 02:47 PM
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Was the last one right? Gas law and all?
bubba13 is offline
Old 04-24-2011, 06:28 PM Thread Starter
Green Broke

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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.

"And somewhere in the northwoods darkness a creature walks upright. And the best advice you may ever get is: Don't go out at night..."
tempest is offline

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