Honors Chemistry- Chapter 9 Homework Packet
Stoichiometry
1) For each of the following conversion factors we use in stoichiometry, fill in the
blanks with the quantities that each relates.
Mole Ratio:
relates
to
Avogadro’s #:
relates
to
Molar Mass:
relates
to
Molarity:
relates
to
2) Write all the possible mole ratios for the following chemical reaction.
2 Cr(ClO3)3 (s) → 2 CrCl3 (s) + 9 O2 (g)
3) An aqueous solution is prepared by dissolving 74.5 grams of KCl in 300 mL of
water. What is the molarity of the solution?
4) What mass of AgBr is needed to make a 1.5 M solution in 500 mL of water?
5) You have 1.16 kg of Mg(NO3)2. What volume of water is needed to make a 0.75
M solution?
6) What volume of 3.00 M NaCl is needed for a reaction that requires 146.3 grams
of NaCl?
Show all of your work when solving the following problems!
7) Hydrogen and oxygen gases react react under a specific set of conditions to
produce water vapor according to the following equation:
2 H2 (g) + O2 (g) → 2 H2O (g)
(a) How many moles of hydrogen are required to produce 5.0 moles of water?
(b) How many moles of oxygen will be produced from 7.5 moles of water?
8) When ethane is combusted, carbon dioxide and water vapor are produced
according to the following equation:
2 C2H6 (g) + 7 O2 (g) → 4 CO2 (g) + 6 H2O (g)
(a) If 4.50 moles of ethane are combusted, what mass (in grams) of carbon
dioxide are produced?
(b) In order to produce 12 moles of water vapor, what mass (in grams) of oxygen
do you need to start with?
9) In a blast furnace, iron (III) oxide is used to produce iron from the following
reaction:
Fe2O3 (s) + 3 CO (g) → 2 Fe (s) + 3 CO2 (g)
(a) If 4.0 kg grams of iron (III) oxide are available to react, how many moles of
CO (g) are also needed?
(b) If you wanted to produce 111.7 grams of solid iron, how many molecules of
CO (g) would you need to start with? (Hint – it’s a three-step conversion)
10) The double replacement reaction between magnesium nitrate and silver
phosphate is shown below. The volume of the reaction vessel is 500 mL.
3 Mg(NO3)2 (aq) + 2 Ag3PO4 (aq) → Mg3(PO4)2 (s) + 6 AgNO3 (aq)
(a) If you start with 445 grams of aqueous magnesium nitrate, what mass (in
grams) of magnesium phosphate will be produced?
(b) If 209 grams of aqueous silver phosphate reacts, what is the molarity of the
aqueous silver nitrate product? (Hint- think about the formula for molarity and how you
can get each part of the equation).
(c) If you started with 0.75 M aqueous magnesium nitrate, how many molecules
of aqueous silver phosphate are needed for the reaction?
11) State the difference between the limiting reactant and the excess reactant(s)?
12) What happens to the chemical reaction when the limiting reactant is completely
used up?
13) What mass of H2 (g) is produced when 110. grams of HCl (aq) reacts with excess
magnesium in the following reaction?
Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2 (g)
14) Consider the following chemical reaction in which 56 grams of CO (g) reacts with
64 grams of O2 (g).
2 CO (g) + O2 (g) → 2 CO2 (g)
a) Is this a limiting reactant problem? How do you know?
b) Which is the limiting reactant? Show calculations below to prove your
answer.
c) What mass of CO2 (g) is produced from the reaction?
d) What is the mass of the excess reactant that remains when the reaction is
over?
15) Consider the following chemical reaction. 245 grams of cobalt (III) nitrate and
68.0 grams of ammonium sulfide are added to water. The volume of the
resulting solution is 750 mL.
2 Co(NO3)3 (aq) + 3 (NH4)2S (aq) → 6 NH4NO3 (aq) + Co2S3 (s)
(a) Is this a limiting reactant problem? How do you know?
(b) What mass (in grams) of precipitate is formed from this reaction? Show all of
your work.
(c) What is the molarity of the aqueous product formed from this reaction? Show
all of your work.
(d) What is the mass of the excess reactant that remains after the reaction is
over?
16) What mass of Al2S3 (s) is produced when 555 grams of aluminum chlorate reacts
with 220 grams of potassium sulfide according to the following equation?
2 Al(ClO3)3 (aq) + 3 K2S (aq)
→
Al2S3 (s)
+ 6 KClO3 (aq)
17) A student reacts benzene, C6H6, with bromine to prepare bromobenzene,
C6H5Br:
C6H6 + Br2 → C6H5Br + HBr
What mass of bromobenzene is produced when 30.0 grams of benzene reacts
with 65.0 grams of bromine?
18) During a chemical reaction, 212.7 grams of chlorine gas reacts with excess
potassium bromide. If the reaction has an 85% yield, what mass of liquid
bromine do you actually produce? (The balanced chemical equation is below.)
Cl2 (g) + 2 KBr (aq)
→ Br2 (l)
+ 2 KCl (aq)
19) The following chemical reaction is a synthesis and combustion reaction. 160.
grams of solid calcium reacts with 48 grams of oxygen gas. 125 grams of solid
calcium oxide is produced. What is the % yield of the reaction?
2 Ca (s) + O2 (g) → 2 CaO (s)