Physical Science Worksheet: Moles
Multiple Choice
1. What is a correct method for calculating the mass of 1.9 x 1023 potassium atoms?
A.
B.
C.
D.
E.
2. What is the correct method to determine the number of oxygen atoms in 8.12g of carbon dioxide?
A.
B.
C.
D.
E.
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1mol CO 2
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8.12g CO 2 
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44.01g CO 2
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1mol CO 2
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2mol O atoms
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1mol O atoms
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23
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6.022 x 10 O atoms
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
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Short Answer
3. In the reaction 2H2O  2H2 + O2, if you start with 2 mol of water, how many moles of hydrogen gas are
produced?
4. In the reaction 2H2O2  2H2O + O2, if you start with 4 mol of H2O2, how many moles of O2 will you end up with?
5. If you start with 5 mol of O2 in the reaction 2Mg + O2  2MgO, how many moles of Mg will you need?
6. In the reaction H2S + 2O2  H2SO4, the law of definite proportions predicts that for every mole of H2S you will
need how many moles of O2?
7. In the reaction 2Mg + O2  2MgO, the law of definite proportions states that for every 2 moles of Mg you will
need how many moles of O2?
8. What is the SI base unit used to measure the amount of a substance?
9. Calculate the number of molecules in 4.0 mol H2O.
10. How many moles of Ag contain 4.49  1023 atoms Ag?
11. Calculate the number of atoms in 13.2 mol copper.
12. Copper (Cu) is a transition element used in the making of coins. Calculate the mass in grams of 0.0420 moles of
copper.
13. Determine the mass in grams of 0.0489 mol cobalt.
14. How many moles of potassium contain 3.70  1023 electrons potassium?
15. How many moles of calcium are in 425 g calcium (Ca)?
16. What is the molar mass of Ca(OH)2?
17. What is the mass of 2.25 moles of sulfuric acid (H2SO4)?
18. How many moles are present in 21.2 g hydrochloric acid?
19. The units of molar mass are
20. The coefficients in a chemical equation represent the
21. A balanced chemical equation allows one to determine the
22. Each of the four types of reaction stoichiometry problems requires using a
23. To balance a chemical equation, it may be necessary to adjust the
24. In the reaction represented by the equation N2 + 3H2  2NH3, what is the mole ratio of nitrogen to ammonia?
25. In the reaction represented by the equation 2Al2O3  4Al + 3O2, what is the mole ratio of aluminum to oxygen?
Physical Science Worksheet: Moles
Answer Section
MULTIPLE CHOICE
1. E
2. A
SHORT ANSWER
3.
4.
5.
6.
7.
8.
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10.
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25.
2 mol
2 mol
10 mol
2 mol
1 mol
Mole
2.4  1024 molecules
0.745 mol
7.95  1024 atoms
2.67 g
2.88 g
0.615 mol
10.6 mol
74.092 g/mol
220 g
0.582 mol
g/mol.
relative numbers of moles of reactants and products.
mole ratio of any two substances in the reaction.
mole ratio.
coefficients.
1:2
4:3