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Lab Section (circle one)
Chapter 6 Homework Problems
CHEM 1A
1. Calculate each of the following quantities:
(a) Total number of ions in 38.1 g of SrF2
(b) Mass in kilograms of 3.58 mol of CuCl2·2H2O
(c) Mass in milligrams of 2.88 x 1022 formula units of Bi(NO3)3·5H2O
2. Cysteine is one of the 20 amino acids commonly found in proteins.
What is the percent composition by mass of carbon (% ( ) C) in
cysteine? (Gray = C, red = O, blue = N, yellow = S, ivory = H)
CHEM 1A – Chapter 6 – Page 1 of 5
3. Ibuprofen, an anti-inflammatory drug and pain reliever is 75.69 % C, 15.51 % O, 8.80 % H by mass.
(a) What is the empirical formula of ibuprofen?
(b) The molar mass of ibuprofen is 206.27 g/mol. What is the molecular formula of ibuprofen
(show work)?
4. Ferrocene, synthesized accidentally in 1951, was the first organic iron compound with Fe–C bonds.
Organometallic chemistry is now a rapidly growing field. Ferrocene contains only Fe, C, and H; and
the combustion analysis of a 0.9437 g sample produced 2.233 g of CO2 and 0.457 g of H2O. What is
the empirical formula of ferrocene?
CHEM 1A – Chapter 6 – Page 2 of 5
5. Balance the following equations (show checks):
(a) The explosion of ammonium nitrate:
___ NH4NO3  ___ N2 + ___ O2 + ___ H2O
(b) The burning of rocket fuel:
___ C2H8N2 + ___ N2O4  ___ N2 + ___ CO2 + ___ H2O
6. Write the balanced formula equation for the reaction of calcium chloride and sodium phosphate to
form calcium phosphate and sodium chloride (show check):
7. A mixture of 0.0375 g of hydrogen (H2) and 0.0185 mol of oxygen (O2) is sparked in a closed
container to produce water.
(a) Write a balanced equation for the reaction.
(b) What is the theoretical yield of water (in grams)?
(c) How many grams of the reactant in excess are left over after the reaction is complete?
CHEM 1A – Chapter 6 – Page 3 of 5
8. The reaction below has a 93.0% yield Ca3N2. If there is excess N2, how many grams of Ca are
required to form 100.0 g Ca3N2 (actual yield Ca3N2)?
3 Ca + N2  Ca3N2
9. Two successive reactions, D  E and E  F, have yields of 48% and 73%, respectively. What is
the overall percent yield for conversion of D to F?
10. Calculate each of the following quantities:
(a) The mass in grams of solid copper (II) nitrate trihydrate required to prepare
500.0 mL of 2.050 M copper (II) nitrate solution.
(b) The volume in milliliters of 2.050 M copper (II) nitrate stock solution that must be diluted
with water to prepare 750.0 mL of 0.8543 M copper (II) nitrate solution
CHEM 1A – Chapter 6 – Page 4 of 5
11. Calculate the final molarity of sodium ions in solution when 1.25 L of 0.250 M sodium sulfate is
mixed with 1.75 L of 0.500 M sodium phosphate.
12. Calculate each of the following quantities:
(a) Molarity of the solution resulting from dissolving 46.0 g of silver nitrate in enough water to
give a final volume of 335 mL
(b) Volume in liters of 0.385 M manganese (II) sulfate that contains 63.0 g of solute
13. How many grams of NaH2PO4 are needed to react with 43.74 mL of 0.285 M NaOH?
NaH2PO4 (s) + 2 NaOH (aq)  Na3PO4 (aq) + 2 H2O (l)
CHEM 1A – Chapter 6 – Page 5 of 5