Chemistry 11
Extra Stuff: Summary of Mole Conversions
1. Make the following conversions, clearly showing your steps. Include proper units in all of
your work and in your answer. Express all molar masses to 1 decimal place.
a. 239.76 g of SeO2 = ? molecules
b. 0.6048 L of NO2 (STP) = ? molecules
c. 7.826 x 1021 molecules of CH4 = ? L (STP)
d. 28.732 g of C3H8 = ? “H” atoms
e. Calculate the density of PCl3 gas at STP.
2. The density of a gas is 2.589 g/L at STP. Calculate the molar mass of the gas.
3. What is the volume occupied by 0.2625 moles of solid silver if it has a density of
10.5 g/mL?
4. An oxide of nitrogen is known to be either NO, N2O, NO2 or N2O4. The mass of 0.800 L of
this gas at STP is found to be 1.643 g.
a. Determine the molar mass of the gas.
b. Give the molecular formula for the gas.
5. Make the following conversions, clearly showing your steps. Include proper units in all of
your work and in your answer. Use your periodic table and express all molar masses to
1 decimal place.
a. 137.5 grams of PCl3 = ? moles
b. 0.00256 moles of SrCrO4 = ? grams
c. 92.288 L of NO2 at STP = ? moles
d. 3.2 x 102 moles of SO3 gas at STP = ? L
e. 806.895 g of PCl5 gas = ? L (STP)
f. 3136 mL of CH4 gas at STP = ? g
g. 2.25 kg of nitrogen gas = ? L (STP)
h. 0.00285 kg of C2H6(g) = ? mL @ STP
6. Describe each as an atom, molecule or a formula unit.
a. CO2
b. KCl
c. C
d. AgNO3
e. NH4CH3COO
f. O2
g. Os
7. Calculate the molar mass using the number of significant figures shown on your quantum
periodic table.
a. C2H6
b. FeCl3
c. Co2(SO4)3·5H2O
d. NH4OH
8. Convert from atoms, molecules, or formula units to grams.
a. 1.33 x 1025 atoms Ag
b. 1.55 x 1016 FU NaCl
c. 2.55 x 10 27 molecules NH3
9. Convert from grams to atoms, molecules, or formula units. Show all work using unit
analysis.
a. 100.0 g H2O
b. 250.g MgCl2
c. 0.266g C6H12
d. 1.2 x 10-4 g Fe
10. Covert each quantity to moles.
a. 500.0 g H2O
b. 5.3 x 1029 FU KBr
c. 0.126 g Co
d. 269g P2O5
e. 25.3 x 1022 molecules C3H8
11. Convert from atoms, molecules, or formula units to grams.
a. 6.55 x 1024 atoms Ag
b. 8.66 x 1026 FU RbCl
c. 5.00 x 10 32 molecules N2H4
d. 5.3 x 1029 FU KBr
e. 25.3 x 1028 molecules C4H10
12. Convert from grams to atoms, molecules, or formula units.
a. 100.0 g H2O2
b. 2.6 g MgF2
c. 0.211 g C5H12
d. 3.33 x 10-2 g Fe
13. Calculate the mass of 4.56 x 1025 atoms of Sr.
14. Calculate the mass of 6.33 x 1020 molecules of CO2.
15. Calculate the mass of 8.66 x 1026 FU of SrO.
16. Calculate the mass of 2.3 x 1028 FU of SrCO3.H2O.
17. Calculate the number of H atoms in 5.02g of CH4. There are 4 atoms of H in one molecule of
CH4.
18. Calculate the number of O atoms in 200.0 g Al2(SO4)3. There are 12 atoms of O in one
formula unit of Al2(SO4)3.
19. Calculate the mass of CaCO3 that contains 2.00 x 1028 atoms of O. There are 3 atoms of O
per one FU of CaCO3.
20. Calculate the mass of Al2(SO4)3 that contains 2.00 x 1028 atoms of O.
21. Calculate the mass of Al2(SO4)3 that contains 2.00 x 1020 atoms of Al.
22. Calculate the number of Al atoms in 500.0g Al2(SO4)3.