Name:_______________________ Period:_____
Math Skills- Mole Conversions
Date:______________
What is the relationship between mass (g), amount of moles (mol), and the
number of atoms in an element????
Mass in
grams (g)
__1 mol__
6.022 x 10 23
atoms
Molar mass
1 mol
Conversion factors
__1 mol__
molar mass
Amount of
element in
moles (mol)
Number of
atoms in
element (atoms)
Conversion factors
6.022 x 10 23
__atoms__
1 mol
DIRECTIONS: Use the above information to help solve the following word
problems. Show all work and units.
1. Uranium, U, (molar mass = 238.03 g/mol) has the largest molar mass of any element
naturally found on Earth. What is the mass (in grams) of 7.50 mol of uranium?
2. Oxygen, O, (molar mass = 32.00 g/mol) is the most common element in Earth’s crust.
Calculate the mass (in grams) of 65.0 mol of oxygen?
3. Large deposits of manganese, Mn, (54.94 g/mol), a metal used to form many different
types of alloys, have been found on the floors of oceans and large lakes. Suppose one
of these deposits contains 383.0 mol of manganese. What is the mass (in grams) of
the manganese deposit?
4. Sodium chloride, NaCl, (58.44 g/mol), commonly known as table salt, is the most
common type of salt. What is the mass (in grams) of 29.0 mol of sodium chloride?
5. The price of gold, Au, (molar mass = 196.97 g/mol) has varied over the last 30 years.
For $100 you could buy as much as 2.6 troy ounces (81.0 g) of gold or as little as 0.13
troy ounces (4.0 g). Calculate the amount of moles that these two masses of gold
represent.
6. Tungsten, W, (molar mass = 183.84 g/mol), whose high melting point makes it
suitable for light bulb filaments, is one of the heavier elements. What is the amount of
moles contained in a 500.0 g sample of tungsten?
7. Carbon, C, (molar mass = 12.01 g/mol) and lead, Pb, (molar mass = 207.2 g/mol) are
the lightest and heaviest members of their elemental group, respectively. Determine
the amount of moles represented by 245.0 g of carbon. Also, determine the amount
of moles represented by 245.0 g of lead.
8. How many moles of lead, Pb, are in 1.50 x 10 12 atoms of lead?
9. How many moles of tin, Sn, are in 2.50 x 10 3 atoms of tin?
10. How many atoms of aluminum, Al, are in 2.75 mol of aluminum?
11. What is the mass (in grams) of 1.20 x 10 8 atoms of copper, Cu? (Hint: this requires 2
steps!)
12. How many atoms of sulfur, S, are in 4.00 g of sulfur? (Hint: this requires 2 steps!)
13. What is the mass (in grams) of 2.00 mol of nitrogen, N?
14. What mass of gold, Au, contains the same number of atoms as 9.0 g of aluminum,
Al?
15. Beaker A contains 2.06 mol of copper (Cu), and Beaker B contains 222.0 grams of
silver (Ag). Which beaker contains the larger mass? Which beaker has the larger
number of atoms? Show all work to support your answers.