Chemist: _______________________________ Team:________
Practice with MOLES
1. Write out the equivalents for the following elements: a. gold, b. carbon, c. aluminum,
d. helium, and e. lead. Example: Gold 1 mole gold  197.0 g Au  6.022 x 1023 atoms Au
2. Write out the equivalents for the following elements and molecules: a. nitrogen gas, N 2,
b. sodium, c. water, d. magnesium, e. table salt, NaCl (follow example in #1)
3. The atomic mass of tungsten, W, is 183.85 amu.
a. write out the equivalents
b. what is the mass in grams of one tungsten atom?
c. how many atoms are in in one milligram of tungsten.
4. Mercury has atomic 200.59 amu. Calculate the:
a. mass of 2.0 x 1015 atoms of Hg.
b. number of atoms in one nanogram of mercury.
5. Determine the:
a. mass of a billion gold (Au) atoms.
b. number of atoms in one ounce of gold.
6. Determine the:
a. mass of one trillion (1012 ) lead (Pb) atoms.
b. number of atoms in one pound of lead.
7.Calculate the number of molecules in an eight-ounce glass of water. (1 lb = 16 oz = 453.6 g)
8. How many electrons are there in:
a. an aluminum atom?
b. a mole of aluminum atoms? (Tip: Use the equivalent that 1 Al atom  13 electrons)
c. 0.2843 moles of aluminum?
d. 0.2843 grams of aluminum?
9. Write out the equivalents for:
a. gallium, Ga, a metal that literally melts in your hands.
b. laughing gas, N2O, one of the first anesthetics used.
c. cane sugar, C12H22O11.
10. Write out the equivalents for:
a. ammonia (NH3).
b. baking soda (NaHCO3).
c. osmium (Os) metal.
11. Convert the following to moles:
a. 0.830 g of strychnine (C21H22N2O2), present in rat poison.
b. two hundred fifty milligrams of aspirin (C9H8O4).
c. a gram of Vitamin C (C6H8O6).
1
12. How many moles are in each of the following:
a. 3.86 g carbon dioxide, CO2.
b. 0.485 g of ethyl alcohol (C2H5OH).
c. 6.00 x 103 g of hydrazine, N2H4, a rocket propellant.
13. Calculate the mass in grams of 5.75 mol of:
a. nitrogen atoms
b. nitrogen molecules (N2)
c. ammonia molecules
For problems 14-16, complete the following table for ethylene glycol, C2H6O2, an antifreeze
used in cars. Each space is a separate problems with separate dimensional analysis.
NUMBERS
NUMBERS
NUMBERS
OF
OF
OF
GRAMS
MOLES
MOLECULES
__________________________________________________
14.
0.1245 grams
_____a______
15. _____a_____
0.0375 mols
16. _____a_____
_____b______
_____b_______
_____b_______
2.0 X 1025 molecules
Complete the following table for acetone, C3H6O, the main component of nail polish remover.
NUMBERS
NUMBERS
NUMBERS
OF
OF
OF
GRAMS
MOLES
MOLECULES
__________________________________________________
17.
1.25 grams
18. _____a_____
19. _____a_____
_____a______
2.5 mols
_____b______
_____b_______
_____b_______
1.33 X 1025 molecules
20. How many copper atoms are in a pre-1983 penny (pure copper, mass = 2.71 grams)
Answers: 3. a. 1 mole=183.85 grams=6.022E23 atoms b. 3.053E-22 grams c. 3.276E18
atoms 4. a. 6.662E-7 grams b. 3.00E12 atoms 5. a. 3.271E-13 grams b. 8.66E22 atoms
6. a. 3.44E-10 grams b. 1.32E24 atoms 7. 7.579E24 molecules 8. a. 13 b. 7.829E24
electrons c. 2.226E24 electrons d. 8.24E22 electrons 11. a. 0.00248 mol b. .00139 mol
c. .00568 mol 12. a. .0877 mol b.0105 mol c. 187 mol 13. a. 80.5 grams b. 161 grams
c. 97.9 grams 14. a. 0.1245 grams b. 0.002006mols c. 1.208E21 molecules 15. a. 2.328 g
b. 0.0375 mols c. 2.258E22 molecules 16. a. 2061g b. 33.2 mols c. 2.0 X 1025 molecules
17. 1.25 grams
b. 0.0215 mols c. 1.30E22 molecules 18. a. 145.2 g b. 2.5 mols
c. 1.51E24 molecules 19. a. 1280 g b. 22.1 mols c. 1.33 X 10 25 molecules 20. 2.57E22 atoms
2