Stoichiometry
By:
Sandra
Ana
Leonard
What is Stoichiometry?
• Stoichiometry is the conversion of mass,
moles, particles, and liters into also mass,
moles, particles, and liters.
http://en.wikipedia.org/wiki/Stoichiometry
IMPORTANT FACT!
• In every stoichiometry problem there is a
mole to mole ratio.
In order to find your answer you need to start
making your given into your want.
How to start?
Read the problem and find out the given and
what you want.
Given & Want
If you have 30 grams of CH4 how many liters of
Cl2 do you need for the reaction below?
CH4 + 3Cl2
CHCl2 + 3HCl
Step 2
• Is the chemical equation balanced?
You look at the chemical equation an see if there
is the same number of elements in each side?
CH4 + 3Cl2
CHCl2 + 3HCl
http://misterguch.brinkster.net/eqnbalance.html
Step 3
• You use the given and convert it into moles
If you have 30 grams of CH4 how many liters of Cl2 do you need for the
reaction below?
CH4 + 3Cl2
CHCl2 + 3HCl
30 grams of CH4 1 mol CH4
HOW DO I FIND THE GRAMS?
How do I find Grams?
ATOMIC MASS of given:
CH4
C is Carbon and H is Hydrogen
Note: there are 4 Hydrogens H4
Use atomic number of each
Element and add
together
4(1.008) + 12.01=
16.042 g of CH4
Step 4
Now that we have the grams we solve the first
step, which is converting it into moles.
30 grams of CH4 1 mol CH4 = 1.88 mol CH4
16.042 g of CH4
Step 5
Good Job! You found the mole, now you need to
convert the want into moles too!
Don’t forget to use your chemical equation
CH4 + 3Cl2
CHCl2 + 3HCl
1.88 mol CH4
3 mol Cl2 = 5.64 mol Cl2
1 mol CH4 3 because in the chemical
equation there is 3
Cl2s . Cl2s because that is the want
Step 6
Now that you did the mole to mole ratio you can
convert it to liters.
Is there something else you have to do before?
- Every mole as gas on 22.4 Liters,
Incorporate that!
… Continued
• Convert from moles into Liters
5.64 mol Cl2
22.4 Liters = 126.336 L Cl2
1 mol Cl2
Results!
If you have 30 grams of CH4 how many liters of
Cl2 do you need for the reaction below?
CH4 + 3Cl2
CHCl2 + 3HCl
From 30 grams of CH4 you get 126.336 L Cl2
What about the others?
This was an example of a mass- liters…
How do you do the others? You might ask your
self..
Well its simple. Just remember that you NEED a
mole to mole. Then you just convert the mole
into the want.
http://wiki.answers.com/Q/How_do_you_convert_from_grams_
to_moles_and_also_from_moles_to_grams
THE END!
Stoichiometry is not hard!