Chem 11 Chapter 3 Assignment
Name:
Mass, Mole, Volume Conversions
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1. 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 (2 marks)
b. 0.00256 moles of SrCrO4 = ? grams (2 marks)
c. 92.288 L of NO2 at STP = ? moles (2 marks)
d. 3.2x102 molesofSO3 gasatSTP=?L(2marks)
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e. 806.895 g of PCl5 gas = ? L (STP) (4 marks)
f. 3136mLofCH4 gasatSTP=?g(4marks)
g. 2.25 kg of nitrogen gas = ? L (STP) (4 marks)
h. 0.00285 kg of C2H6(g) = ? mL (4 marks)
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2. 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 (4 marks) b.
0.6048 L of NO2 (STP) = ? molecules (4 marks)
c.
7.826 x 1021 molecules of CH4 = ? L (STP) (4 marks) d.
28.732 g of C3H8 = ? “H” atoms (4 marks)
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3. Calculate the density of PCl3 gas at STP. (4 marks)
4. The density of a gas is 2.589 g/L at STP. Calculate the molar
mass of the gas. (4 marks) 5. What is the volume occupied by 0.2625 moles of solid silver
if it has a density of 10.5 g/mL? (4 marks) 6. 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. (4 marks)
b. Give the molecular formula for the gas. (1 mark)
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Percent Composition, Empirical and Molecular
Formulas, Molarity Calculations and Dilution
7. Find the percent composition (% by mass of each element) in
the following compound: Ba3(PO4)2. Show your work. (3 marks)
Answer ______%Ba, ______%P, ______%O
8. Calculate the percent by mass of water (H2O) in strontium
hydroxide octahydrate,Sr(OH)2.8H2O. (2 marks)
Answer __________% H2O
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9. A compound was analyzed and the following results were
obtained: Molar mass: 162.0 g/mol, Mass of sample: 0.8821g,
Mass of hydrogen: 0.0220 g, Mass of phosphorus: 0.3374g,
Mass of oxygen: the remainder of the sample is oxygen
a. Determine the mass of oxygen in the sample. (1 mark)
b. Determine the empirical formula for this compound. (4 marks)
c. Determine the molecular formula for this compound. (2 marks)
10. 89.523 g of sodium sulphate Na2SO4 are dissolved in enough
water to form 850.0 mL of solution. Calculate the molar
concentration of Na2SO4 ([Na2SO4]) Include proper units in your
work and in your answers. (2 marks)
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11. Calculate the mass of potassium carbonate (K2CO3) needed
to make 400.0 mL of a 0.200 M solution of K2CO3. (2
marks)
12. What volume of 2.50 M Li2SO3 would need to be
evaporated in order to obtain 422.55 g of solid Li2SO3? (2
marks) 13.150.0 mL of water are added to 200.0 mL of 0.60 M HNO3 .
Calculate the final [HNO3]. (2 marks) 14.What volume of water needs to be added to 50.0 mL of 6.00
M H2SO4 in order to bring the concentration down to 2.50
M? (2 marks)
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15.What volume of 12.0 M HCl must be used in order to
produce 500.0 mL of 0.250 M HCl? (2 marks)
16.200.0 mL of 0.450 M NaOH is diluted to a total volume of
1.00 L. Calculate the final concentration of NaOH. (2 marks)
17.Give directions on how to make 400.0 mL of 0.020 M
KMnO4 using solid KMnO4 and water. (2 marks)
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