Chemistry Reference
In-Depth Information
4.
How many moles of propane must react completely to generate 30
moles of carbon dioxide?
5.
How many moles of oxygen must react with an excess of propane to
generate 8 moles of water?
Base your answers to questions 6-10 on the following balanced chemi-
cal equation:
3H
2
+ N
2
2NH
3
hydrogen + nitrogen
ammonia
6.
How many moles of nitrogen would be required to react completely
with 9 moles of hydrogen?
7.
How many moles of hydrogen would be required to react completely
with 5 moles of nitrogen?
8.
How many moles of hydrogen would be required to produce 1 mole
of ammonia?
9. How many moles of nitrogen would be required to produce 10 moles
of ammonia?
10. How many moles of ammonia could be generated if you started with
9 moles of hydrogen and 2 moles of nitrogen?
Lesson 7-4: Mass-Mass Problems
Now you are ready to try your first complete stoichiometry problems,
where you quantitatively analyze chemical reactions. The mass-mass prob-
lem is where you either know the mass of the product that you want to
produce and calculate the mass of the reactant(s) you start with, or you
know the mass of the reactant(s) you start with and calculate the mass of
the product you will end up with. As with mole conversion problems, there
are a variety of these types of problems, with a varying range of difficulty.
We will start off with some of the easier types and work our way up to
harder problems.
Magnesium is a metal that emits a blinding white light when it burns in
the presence of oxygen. The sparklers that you see on the Fourth of July and
the road flares that you see at the scene of an accident contain magnesium.
In the chemistry lab, you may have seen magnesium in the form of a metal-
lic strip or ribbon. Let's begin with a problem where you want to calculate
the amount of magnesium oxide you will produce when you burn 2.00 g of
pure magnesium ribbon in an excess of oxygen. When we say an “excess” of
