Chemistry Reference
In-Depth Information
Now, practice the following problems until you feel comfortable with
mole conversions, and then move on to the next lesson.
Lesson 7-2 Review
1.
Find the volume that 4.50 moles of nitrogen gas will occupy at STP.
2.
Calculate the mass of 2.50 moles of NaBr.
3.
How many moles of carbon would 50.0 g of carbon represent?
4.
How many molecules does 1.88 moles of water represent?
5.
How many moles of helium gas would occupy 75.0 dm
3
at STP?
6.
How many moles of molecules would 1.81 × 10
24
molecules of
glucose represent?
7.
How many molecules would 45.0 g of water represent?
8.
How much space would 85.0 g of neon gas occupy at STP?
9. How many molecules of carbon dioxide gas would occupy 67.5 dm
3
at
STP?
10. What would be the mass of 9.65 × 10
25
molecules of water?
Lesson 7-3: Mole-Mole Problems
Mole-mole problems are sort of like “introductory,” or “skill-building,”
problems that will help you practice using the molar ratios given by bal-
anced chemical reactions. The harder stoichiometry problems, which we
will begin in the next lesson, all make use of mole-mole problems as a step
in the problem-solving process. This lesson will give you an opportunity to
become comfortable with the molar ratio without worrying about more
complex problems at the same time.
Look at the following problem.
Example 1
How many moles of oxygen (O
2
) are required to react completely
with 3 moles of glucose (C
6
H
12
O
6
) according to the balanced
chemical equation shown here?
C
6
H
12
O
6
+ 6O
2
6H
2
O + 6CO
2
glucose + oxygen
water + carbon dioxide
