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WorksheetsCh. 12 (Stoichiometry)
Total questions: 20
Worksheet time: 4hrs 48mins
Chemists normally use an excess of one reactant in a chemical reaction because —
the reaction will continue until all of the limiting reactant is consumed
the reaction will continue until all of the excess reactant is consumed
reactions do not take place unless there are unequal amounts of reactants
reactions occur too quickly if equal amounts of reactants are used
What is the first thing you must do to solve a stoichiometric problem?
Find the limiting reactant.
Find the excess reactant.
Write a balanced chemical equation.
Find the empirical formula.
The actual yield of a product is
a negative Value.
a negative Value.
the same as its theoretical yield.
measured experimentally.
Which of the following is a correct mole ratio for the following equation?
2Al(s) + 3Br2(l) → 2AlBr3(s)
2 mol Al : 3 mol Br
3 mol Br2 : 2 mol Al
2 mol AlBr3 : 1 mol Br2
2 mol Br : 2 mol Al
A chemical reaction equation must be ____ in order to make stoichiometric calculations.
measured
controlled
balanced
produced
How many moles of carbon dioxide is produced when 6.3 mol of propane gas is burned in excess oxygen?
C3H8 + 5O2 → 3CO2 + 4H2O
2.1 mol
18.9 mol
6.3 mol
10.5 mol
You calculate the theoretical yield of a chemical reaction starting with 33.0g of reactant is 17.0g of product. What is the percent yield if the actual yield is 13.4g of product?
30.4%
131%
78.8%
40.6%
The amount of product formed during a reaction depends on the
limiting reactant
excess reactant
reaction rate
None of these answers
In the following reaction, how many moles of NaCN are required to react with 7 mol of Au?
4Au(s) + 8NaCN(aq) + O2(g) + 2H2O(l) → 4NaAu(CN)2(aq) + 4NaOH(aq)
14 mol
3.5 mol
7 mol
8 mol
Stoichiometry is the study of quantitative relationships between amounts of —
the reactants and products of a chemical reaction relative to time
the products of a chemical reaction only
the reactants and products of a chemical reaction
the reactants of a chemical reaction only
The amount of product that can be produced from a given amount of reactants based on stoichiometric calculations is:
actual yield
percent yield
theoretical yield
stoichiometric yield
What law are all stoichiometric calculations based on?
law of definite proportions
law of conservation of mass
law of conservation of energy
none of these answers
What is the ratio between the coefficients of any two substances in a balanced equation?
Molar mass balanced equation
Mole ratio
Quadratic equation
Chemical formula
The substance that limits the extent of a chemical reaction has a special name. What is this substance called?
Limiting reactant
Limiting product
Excess reactant
Excess product
The mass of the final product in a chemical reaction is based on what?
the amount of excess reactant
the amount of limiting reactant
the presence of a catalyst
the amount of O2 present
A(n) ______________________ is a reactant that has a portion remaining after the reaction has stopped.
percent yield
stoichiometry
excess reactant
theoretical yield
limiting reactant
The ratio of the actual yield to the theoretical yield expressed as a percent is called the ______________________.
percent yield
stoichiometry
excess reactant
theoretical yield
limiting reactant
The study of the quantitative relationships among the amounts of reactants used and the amounts of products formed by a chemical reaction is called ______________________.
percent yield
stoichiometry
excess reactant
theoretical yield
limiting reactant
The reactant that limits the extent of the reaction is called the ______________________.
percent yield
stoichiometry
excess reactant
theoretical yield
limiting reactant
The ______________________ is the maximum amount of product that can be produced from a given amount of reactant.
percent yield
stoichiometry
excess reactant
theoretical yield
limiting reactant
