Transcript Unit 11: Stoichiometry

Unit 11: Stoichiometry
MOLE RATIOS
MOLE TO MOLE CONVERSIONS
Irrelevant Information to Take Your Mind Off of
Stoichiometry
The first person to use the word “stoichiometry” was
Nicephorus I, the ecumenical Patriarch of Constantinople in
the early 9th century. However, the term as he used it refers
to the number of lines of text in the New Testament. This
suggests that the term “stoichiometry” has been annoying
people for over a millennium.
Image: Classical Numismatic
Some stoich fun:
Stoichiometry
What is stoichiometry?
The quantitative relationships between the amounts of reactants
used and the amounts of products formed by a chemical reaction.
Which is just a fancy way of saying:
◦ “the method you use to figure out how much of a chemical you can make, or
how much you need to produce a substance, during a reaction.”
In order to do Stoich:
1. Know how to balance chemical equations
2. Know how to convert grams to moles/moles to grams
3. How to use mole ratios
Can you do 1 and 2?
Mole Ratios
Ratio- a relationship between two numbers of the same kind.
2H2 + O2  2H2O
*Use the coefficients of the balanced chemical reaction to determine the mole ratios.
Ratios:
2 hydrogen for 1 oxygen
2 hydrogen for 2 water
1 oxygen for 2 water
Mole Ratios
Balance the reactions and then determine the mole ratios:
1.
__Fe + __O2 ⇒ __Fe2O3
2. __C3H8 + __O2 ⇒ __CO2 + __H2O
Mole Ratios:
Knowing the mole ratios allows you to begin doing stoichiometry:
2H2 + O2 
2H2O
If we have 5 moles of hydrogen reacting, how many moles of water are formed?
The Amount Given
5 moles H2
2 moles H2O
= 5 moles H2O
2 moles H2
Mole ratio between the two compounds in the problem
Mole to Mole Conversions:
We can determine the number of moles needed to
produce, or how much of a substance will be
produced from the number of moles we have to start
with.
Mole to Mole Conversions:
____K + ____H2O  ____KOH + _____ H2
If there are 3.5 moles of potassium reacting, how many moles of hydrogen will form?
Mole to Mole Conversions:
____Fe + ____O2  _____Fe2O3
If you only had 0.45 moles of Fe how many moles of Fe2O3 would you produce?
How many moles of O2 were used?
Mole to Mole Conversions:
__C3H8 + __O2 ⇒ __CO2 + __H2O
If 7.8 moles of O2 are used how much C3H8 was also used?
How many moles of CO2 were produced?
Mole to Mole Conversions:
__AgNO3 + __Cu ⇒ __Cu(NO3)2 + __Ag
10.2 moles Cu are used to react with AgNO3, how many moles of AgNO3 were used to
react?
How many moles of Silver are produced?