Chemistry
Stoichiometry
• Calculations involving quantities of consumed reactants and formed products based on a BALANCED chemical equation. Mass
Molar
Mass
Mole
Coeff
Bal Eqn
Mole
Molar
Mass
Mass
Example 2
• The Haber Process involves reacting gaseous nitrogen and gaseous hydrogen to form ammonia. Determine the mass in grams of hydrogen gas required to form
1.00 x 103 g ammonia.
Your Turn 2
• If you react 52.9 g of potassium chlorate
(KClO3) with excess phosphorus, what mass of tetraphosphorus decoxide (P4O10) would be produced.
KClO3 (s) + P4 (s) → P4O10 (s) + KCl (s)
Answer: 36.8 g P4O10
Stoichiometry
• In the real world, reactions do not always have 100% efficiency. • Often, use an excess of one of the reactants (usually the cheaper one).
• Limiting Reactant – reactant that will be totally consumed. • Excess Reactant – will not be totally consumed; will have left over.
• The maximum amount of product (theoretical yield) that can be obtained in a chemical reaction is based on the limiting reactant.
– Need to fully “GRASP”
Example 3
• Consider the reaction:
2Sb (s) + 3I2 (s) → 2SbI3 (s)
Determine the limiting reactant and the theoretical yield (in grams) when 1.20 g of
Sb and 2.40 g I2 are mixed. What mass of excess reactant is left when the reaction is complete? Your Turn 3
• Consider the reaction:
Ag2O (s) + 2C10H10N4SO2 (s) → 2AgC10H9N4SO2 (s) + H2O (l)
If 25.0 g of Ag2O is reacted with 50.0 g of
C10H10N4SO2, what mass of
AgC10H9N4SO2 can be produced assuming
100% yield?
Answer: 71.4 g AgC10H9N4SO2
Summary on LR
1. Calculate the amount of product that would be formed if the first reactant were completely consumed. 2. Do #1 for the other reactant/s (separate calculation). 3. Choose the smaller of the two amounts of product from #s 1 and 2. This is the theoretical yield and the reactant that produces the smaller amount is the limiting reactant. The other reactant/s is/are
• Calculations involving quantities of consumed reactants and formed products based on a BALANCED chemical equation. Mass
Molar
Mass
Mole
Coeff
Bal Eqn
Mole
Molar
Mass
Mass
Example 2
• The Haber Process involves reacting gaseous nitrogen and gaseous hydrogen to form ammonia. Determine the mass in grams of hydrogen gas required to form
1.00 x 103 g ammonia.
Your Turn 2
• If you react 52.9 g of potassium chlorate
(KClO3) with excess phosphorus, what mass of tetraphosphorus decoxide (P4O10) would be produced.
KClO3 (s) + P4 (s) → P4O10 (s) + KCl (s)
Answer: 36.8 g P4O10
Stoichiometry
• In the real world, reactions do not always have 100% efficiency. • Often, use an excess of one of the reactants (usually the cheaper one).
• Limiting Reactant – reactant that will be totally consumed. • Excess Reactant – will not be totally consumed; will have left over.
• The maximum amount of product (theoretical yield) that can be obtained in a chemical reaction is based on the limiting reactant.
– Need to fully “GRASP”
Example 3
• Consider the reaction:
2Sb (s) + 3I2 (s) → 2SbI3 (s)
Determine the limiting reactant and the theoretical yield (in grams) when 1.20 g of
Sb and 2.40 g I2 are mixed. What mass of excess reactant is left when the reaction is complete? Your Turn 3
• Consider the reaction:
Ag2O (s) + 2C10H10N4SO2 (s) → 2AgC10H9N4SO2 (s) + H2O (l)
If 25.0 g of Ag2O is reacted with 50.0 g of
C10H10N4SO2, what mass of
AgC10H9N4SO2 can be produced assuming
100% yield?
Answer: 71.4 g AgC10H9N4SO2
Summary on LR
1. Calculate the amount of product that would be formed if the first reactant were completely consumed. 2. Do #1 for the other reactant/s (separate calculation). 3. Choose the smaller of the two amounts of product from #s 1 and 2. This is the theoretical yield and the reactant that produces the smaller amount is the limiting reactant. The other reactant/s is/are