K7: K-3W/K-4 W/UNIT K STUDY GUIDE
SUPPLEMENTARY STOICHIOMETRY PRACTICE PROBLEMS
1. Bromine liquid (Br2) reacts with aqueous sodium iodide (NaI) in a single replacement reaction
to produce aqueous sodium bromide (NaBr) and solid iodine crystals (I2).
a) Write the balanced reaction equation.
b) How many moles of sodium bromide could be produced from 0.172 moles of bromine liquid?
2. Diatomic oxygen gas reacts with diatomic nitrogen gas to yield nitrogen dioxide gas.
a) Write the balanced reaction equation.
b) Assuming that all gases are at STP, find the volume of nitrogen dioxide gas that could be
produced from 71.11 L of diatomic nitrogen gas.
3. Diatomic oxygen gas reacts with calcium metal to form calcium oxide solid (CaO).
a) Write the balanced reaction equation.
b) How many formula units of CaO can be produced from 4.9105molecules of diatomic oxygen
gas?
4. Given the balanced chemical equation for the decomposition of phosphorus oxyfluoride gas
(POF3),
4POF3 (g)  P4 (s) + 2O2 (g) + 6F2 (g)
What volume, at STP, of fluorine gas (F2) would be produced by the decomposition of 9.221025
molecules of phosphorus oxyfluoride?
5. Calculate the mass of mercury metal (Hg) that is required to produce 39.8 g of mercury (I) oxide
(Hg2O) according to the following balanced chemical reaction equation.
4Hg (l) + O2 (g)  2 Hg2O (s)
6. Find the number of grams of sulfur (S) that is produced when 1.87 L of oxygen gas (O2) at STP is
also produced by the decomposition of sulfur trioxide gas (SO3) according to this balanced
chemical equation:
2SO3 (g)  2S(s) + 3O2 (g)
7. Sodium chloride (NaCl) is produced when sodium metal (Na) is reacted with diatomic chlorine
gas (Cl2)
a) Write the balanced chemical equation.
b) How many formula units of sodium chloride (NaCl) are produced by the reaction of 40.3
grams of diatomic chlorine (Cl2) gas?
8. Sodium reacts with water to from sodium hydroxide and hydrogen gas:
2Na (s) + 2H2O (l)  2NaOH (aq) + H2 (g)
a) If 90.0 g of sodium is dropped into 80.0 g of water, which reactant is in excess, and how
much is left over?
b) What volume of H2 at STP would be produced from the above amounts of reactants
(remember to use the limiting reactant as the basis for your calculations)?
9. Phosphorus burns in oxygen gas to produce phosphorus (V) oxide (P4O10):
P4 (s) + 5O2 (g)  P4O10 (g)
a) If 2.50 g P4 is ignited in a flask with 0.75 L O2 at STP, which reactant is in excess, and how
much is left over?
b) How many grams of P4O10 are formed (remember to use the limiting reactant as your basis)?
K7: K-3W/K-4 W/UNIT K STUDY GUIDE
UNIT K STUDY GUIDE

VOCABULARY/CONCEPTS
It is likely that questions concerning vocabulary will take the form of multiple choice or
matching questions.
In the open response section, you should be able to do the following:
1.
You must be able to prove your ability to determine if an equation is balanced by
showing all work leading to your conclusion. THIS MEANS THAT YOU MUST
SHOW THE ATOM COUNTING METHOD THAT WE HAVE USED IN CLASS.
2.
You must be able to balance any equation to conform to the Law of Conservation of
Mass given the chemical formulas of the reactants and products. This will involve
supplying coefficients when necessary while leaving subscripts unchanged.
3.
You must be able to determine the type of reaction (synthesis/direct combination,
decomposition/analysis, single replacement, double replacement) given the chemical
formulas of the reactants and products.
4.
Given the relative activities of elements, you should be able to determine if a single
replacement reaction will take place.
5.
You must show that you understand the conditions for a double replacement reaction
to take place (formation of a gas, formation of water, formation of a precipitate)
given solubility data and the understanding of which elements form diatomic gas
molecules (for example, hydrogen, nitrogen, oxygen, fluorine, chlorine)
6.
Given an interpretation or word equation and the naming compounds flow sheet, you
should be able to write the formulas of reactants and products of an unbalanced
equation.
7.
list what information can derived from the coefficients of a balanced equation
(moles, molecules/particles, liters, etc.),
determine the number of moles, molecules/particles, and liters represented by the
coefficients of a balanced equation,
convert the number of moles of a substance into sample mass,
convert the number of moles of a substance into molecules/particles,
convert the number of moles of a substance into liters,
use stoichiometric analysis and dimensional analysis (factor label method) to solve
problems involving the calculation of the mass, moles, particles and/or liters of a
product given quantitative information about a reactant,
use stoichiometric analysis and dimensional analysis (factor label method) to solve
problems involving the calculation of the mass, moles, particles and/or volume (in
dm3) of a product given quantitative information about a product.
Given a balanced chemical reaction equation and starting reactant quantities, be able
to determine which reactant limits (or is in excess), and determine the quantities of
products produced, and how much excess reactant remains at the end of the reaction.
Once a theoretical yield has been determined, use this information and actual yield
information to calculate percent yield for a reaction.
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