Stoichiometry
One last Molar Conversion…
Molar Volume!!
______ L/mol
at STP.
(STP = Standard
Temperature
and Pressure)
When you
see…
grams
(kg, mg, etc.)
You
need
this!
Molar
Mass
What is it?
Periodic Table
_____ g ___ = 1 mol ___
(example: 12 g C = 1 mol C)
Avogadro’s
atoms,
Number
particles,
molecules,
formula units,
6.02 x 1023
Liters
Molar
(cm3, mL, etc.) Volume
22.4 L/mol
particles/mol
What is STOICHIOMETRY?!@!?


Stoichiometry refers to the calculations of chemical
quantities from balanced chemical equations.
Allows us to relate masses of reactants and products
Interpreting Chemical Equations
Write the synthesis reaction of nitrogen reacting with
hydrogen forming nitrogen trihydride. ……..and balance!
___
1 N2 (g) + ___
3 H2 (g)  ___
2 NH3 (g)
coefficient – also represents ONE mole of N2
Mole ratios – the ratio of moles of one substance to
moles of another substance in a balanced
chemical equation
Interpreting Chemical Equations
1 N2 (g) + ___
3 H2 (g)  ___
2 NH3 (g)
___
Mole ratios come from the coefficients of a balanced
equation.
This is also known as the mole
conversion
factor.
Example Mole Ratios:
1 mol N2
3 mol H2
3 mol H2
1 mol N2
2 mol NH3
1 mol N2
3 mol H2
2 mol NH3
Interpreting Chemical Equations
1 N2 (g) + ___
3 H2 (g)  ___
2 NH3 (g)
___
What other information can we get from the equation?
Mass A to Moles B
1 N2 (g) + ___
3 H2 (g)  ___
2 NH3 (g)
___
How many moles of ammonia (NH3) can be made from
reacting 39.0 grams of nitrogen reacting with an excess of
hydrogen?
Mass A to Volume B
1 N2 (g) + ___
3 H2 (g)  ___
2 NH3 (g)
___
How many liters of nitrogen gas need to completely react
with 25 grams of hydrogen to produce ammonia at STP?
You Try
(assume STP for the following problems)
How many moles of nitrogen (N2) are needed to completely
react with 6 moles of hydrogen to produce ammonia?
How many liters of ammonia would be produced when 5.5
grams of nitrogen reacts completely with hydrogen.
How many grams of H2 are needed to react with an excess of
nitrogen to make 25.5 grams of NH3?
Excess means extra! We definitely have
enough of that substance for the reaction to
occur, so we can ignore it! The limiting
reactant is what limits how far our reaction
can go.
Exit Ticket

Using the synthesis reaction of ammonia from your
handout, how many grams of ammonia can be produced if
25 liters of hydrogen gas reacts with an excess
amount of nitrogen?
Exit Ticket

Using the following balanced reaction:
2 H2 + O2  2 H2O

How many grams of water can be produced if 25 liters
of hydrogen gas reacts with an excess amount of
oxygen?
I’m a
Hint #1: Figure out what
you are looking for and
what you have
Once you got that,
find either the moalr
mass, particles or
molar volume for
those two substances!
mole!
Exit Ticket

Using the synthesis reaction of ammonia from your
handout, how many grams of ammonia can be produced if
25 liters of hydrogen gas reacts with an excess
amount of nitrogen?