Stoichiometry Answer Key
Vocabulary: Avogadro’s number, balanced equation, cancel, coefficient, dimensional
analysis, molar mass, mole, molecular mass, stoichiometry
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
[Note: The purpose of these questions is to activate prior knowledge and get students
thinking. Students are not expected to know the answers to the Prior Knowledge Questions.]
1. A 250 mL glass of orange juice contains 22 grams of sugar. How much sugar is
in a two-liter (2,000 mL) bottle of orange juice? 176 grams of sugar
2. It requires two sticks of butter to make a batch of 20 cookies. How much butter
will it take to make 150 cookies? 15 sticks of butter
Gizmo Warm-up
Just as a cook follows a recipe to decide
how much of each ingredient to add, a
chemist uses stoichiometry to determine
the amounts of substances involved in
chemical reactions. The Stoichiometry
Gizmo™ allows you to try your hand at
figuring out the amounts of reactants and
products that take part in a chemical
reaction.
To begin, check that this equation is
shown: Fe2O3 + 3CO 2Fe + 3CO2
1. Look at the coefficients (such as the “3” in 3CO) in front of each substance in
the equation. The coefficients tell you how many molecules or atoms take part
in a chemical reaction. In the spaces below, list the number of each molecule or
atom in the equation:
Fe2O3 1 CO 3 Fe 2 CO2 3
2. In a balanced equation, the same number of each kind of atom is shown on
each side of the equation. Calculate the number of iron (Fe), oxygen (O), and
carbon atoms (C).
Reactants Iron: 2 Oxygen: 6 Carbon: 3
Products Iron: 2 Oxygen: 6 Carbon: 3
, This study source was downloaded by 100000847097152 from CourseHero.com on 11-15-2022 10:34:48 GMT -06:00
Vocabulary: Avogadro’s number, balanced equation, cancel, coefficient, dimensional
analysis, molar mass, mole, molecular mass, stoichiometry
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
[Note: The purpose of these questions is to activate prior knowledge and get students
thinking. Students are not expected to know the answers to the Prior Knowledge Questions.]
1. A 250 mL glass of orange juice contains 22 grams of sugar. How much sugar is
in a two-liter (2,000 mL) bottle of orange juice? 176 grams of sugar
2. It requires two sticks of butter to make a batch of 20 cookies. How much butter
will it take to make 150 cookies? 15 sticks of butter
Gizmo Warm-up
Just as a cook follows a recipe to decide
how much of each ingredient to add, a
chemist uses stoichiometry to determine
the amounts of substances involved in
chemical reactions. The Stoichiometry
Gizmo™ allows you to try your hand at
figuring out the amounts of reactants and
products that take part in a chemical
reaction.
To begin, check that this equation is
shown: Fe2O3 + 3CO 2Fe + 3CO2
1. Look at the coefficients (such as the “3” in 3CO) in front of each substance in
the equation. The coefficients tell you how many molecules or atoms take part
in a chemical reaction. In the spaces below, list the number of each molecule or
atom in the equation:
Fe2O3 1 CO 3 Fe 2 CO2 3
2. In a balanced equation, the same number of each kind of atom is shown on
each side of the equation. Calculate the number of iron (Fe), oxygen (O), and
carbon atoms (C).
Reactants Iron: 2 Oxygen: 6 Carbon: 3
Products Iron: 2 Oxygen: 6 Carbon: 3
, This study source was downloaded by 100000847097152 from CourseHero.com on 11-15-2022 10:34:48 GMT -06:00
