Calculation of Molar Mass Worksheet

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Name _________________________________________
Period ______
Mole Conversions Worksheet
First know that:
 Mass is measured in grams. “Find the mass of” means find the number of grams.
 Volume is measured in liters. “What is the volume of” means find the number of liters.
 Particles are atoms, molecules or formula units.
Converting between
grams and moles: use molar mass
(add up masses from periodic table)
liters and moles of a gas at STP
particles and moles (particles are
atoms, molecules or formula units)
to moles
1 mol
XX.X g
from moles
XX.X g
mol
1 mol
22.4 L
22.4 L
mol
1 mol
6.02 x 1023 particles
6.02 x 1023 particles
mol
Mole conversion steps:
1. Identify what you are converting from and what you are converting to.
2. Determine if the conversion is one or two steps:
a. If either the from or the to is moles, then the conversion requires only a single step.
b. If neither the from nor the to is moles, then two steps are required. In the first step you will
convert to moles and in the second step, from moles.
3. Set up the problem:
a. Write the given value (the from).
b. Multiply by the conversion factor (see table above). What you are converting to goes in the
numerator and what you are converting from goes in the denominator.
4. Solve the problem. Show how units cancel and use the correct number of significant digits.
One step example
What is the mass of 1.673 moles of copper?
From: moles
To: grams
1.673 mol x
63.546 g
mol = 106.3 g
Two step example
What is the volume of 9.36 g of methane gas
(CH4) at STP?
From: grams
To: liters
mol
22.4 L
9.36 g x 16.04 g x mol = 13.1 L
Problems
1. What is the mass of 0.46 mol of MgCl2?
From:
To:
3. How many liters at STP is 0.22 mol of neon?
From:
To:
2. How many moles is 1.438 g of HCl?
From:
To:
4. How many atoms is 0.85 g of gold (Au)?
From:
To:
5. What is the volume at STP of 33.1 g of
hydrogen gas (H2)?
From:
To:
11. What is the mass of 837 L of methane gas
(CH4) at STP?
From:
To:
6. How many atoms are there in 7.2 moles of
iron (Fe)?
From:
To:
12. How many molecules are in a weather balloon
filled with 102 L of air at STP?
From:
To:
7. How many molecules are in 3.78 x 10-3 moles
of water?
From:
To:
13. A container holds 10.4 L at STP of SO2 gas.
What is the mass of the gas?
From:
To:
8. How many moles is 5.38 x 1021 atoms of
sodium?
From:
To:
14. What is the mass of 3.51 x 1025 molecules of
acetylene gas (C2H2)?
From:
To:
9. What is the volume at STP of 2.74 x 1024
atoms of argon gas?
From:
To:
15. If 437 g of helium are released into a balloon
at STP, what will the volume be?
From:
To:
10. How many moles is 12.56 L of carbon dioxide
gas at STP?
From:
To:
16. How many molecules of hemoglobin are there
in 8.4 x 10-3 g? The molar mass of
hemoglobin is approximately 68,000 g/mole.
From:
To:
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