Name: _________________________________ Period: _________
Unit 6 Review: The Mole
Fill in the blanks:
1. Formula mass is used for ______________ compounds. The formula mass
for KBr is _________ amu.
2. Molecular mass is used for ______________ compounds. The molecular
mass of P2O3 is ___________ amu.
3. A mole is a unit of measurement that is equal to _______________
representative particles.
4. Molar mass is the ________ in grams of one _________ of a substance.
Molar Mass:
5. The molar mass of CaCO3 is ______________.
6. The molar mass of diphosphorus tetraoxide is ______________.
Conversions: (SHOW ALL WORK AND UNITS!)
7. What is the mass of 2.55 moles of Zn?
8. How many moles is 60 grams of barium chloride?
9. How many molecule are there in 2.5 moles of water?
10. How many moles are equal to 1.7 X 1022 atoms of calcium?
11. How many molecules are in 14.2 grams of silver (I) nitrate?
12. How many grams are in 6.52E23 formula unit of NaCl?
Percent composition (Percent by Mass)
13. Find the percent composition of Al2(SO4)3
14. Find the percent composition of Be(OH)2
15. Which of the following iron compounds contain the greatest percentage of
iron: pyrite (FeS2), hematite (Fe2O3), siderite (FeCO3)?
16. Which of the following compounds has a greater percent by mass of
chromium, K2CrO4, or K2Cr2O7?
Empirical and Molecular Formulas:
17. Find the empirical formula of a compound that has 74.51%Pb and 25.49%Cl
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18. Empirical formula = NH2
Molar mass = 32.06 g/mol. Find the molecular
formula.
19. You have a compound with 8 carbon atoms, 8 hydrogen atoms, 2 nitrogen
atoms, and 2 oxygen atoms.
a. Write the molecular formula for this compound
b. Write the empirical formula for this compound
c. Write the molar mass for this compound
20. A component of protein called serine has an approximate molar mass of 100
g/mole. If the percent composition is as follows, what is the empirical and
molecular formula of serine?
C = 34.95 % H= 6.844 % O = 46.56 % N= 13.59 %
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