What is Stoichiometry The study of the mass relationships in chemical reactions Stoichiometry can be used to find the masses of compounds and elements based on the ratios found in chemical equations ID: 919415
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Slide1
Stoichiometry
A Survival Guide for the Intrepid Chemistry Student
Slide2What is Stoichiometry?
The study of the mass relationships in chemical reactions.
Stoichiometry can be used to find the masses of compounds and elements based on the ratios found in chemical equations.
Stoichiometric calculations are based on the relationship between mass and moles i.e. molar mass.
Slide3Keys to Success
Make a plan and follow through.
Make sure
you have a complete balanced equation.
Make the correct mole-mass conversions.
Use the correct ratios.
Use the correct labels and units throughout.
Slide4Steps to Solve Stoichiometric Problems.
1) Write and balance the equation.
2) Determine the
given
quantity and the
wanted
quantity.
3) If given is in grams, convert to moles, (divide by the molar mass).
4) Use the balanced equation to find the molar ratio between the
wanted
and the
given
.
5) Multiply the
given
by the molar ratio, (wanted/given ).
6) If the
wanted
is requested in moles, you are finished.
7) If the
wanted
is requested in grams, multiply by the molar mass.
Slide5Steps to Solve Stoichiometric Problems.
Problem:
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
Slide6Steps to Solve Stoichiometric Problems.
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
1) Write and balance the equation
.
2
AgNO
3
+ MgSO
4
Ag
2
SO
4
+ Mg(NO
3
)
2
Slide7Steps to Solve Stoichiometric Problems.
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
2) Determine the
given
quantity and the
wanted
quantity.
Wanted: _______ g Ag
2
SO
4
Given: 35.0 g AgNO
3
Slide8Steps to Solve Stoichiometric Problems.
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
3) If given is in grams, convert to moles, (divide by the molar mass).
35.0 g AgNO
3
/169.9 g/
mol
= 0.206
mol
AgNO
3
Slide9Steps to Solve Stoichiometric Problems.
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
4) Use the balanced equation to find the molar ratio between the
wanted
and the
given
.
1
mol
Ag
2
SO
4
: 2
mol
AgNO
3
Slide10Steps to Solve Stoichiometric Problems.
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
5) Multiply the
given
by the molar ratio, (wanted/given ).
0.206
mol
AgNO
3
x ( 1mol Ag
2
SO
4
/ 2
mol
AgNO
3
) =
0.103
mol
Ag
2
SO
4
Slide11Steps to Solve Stoichiometric Problems.
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
6) If the
wanted
is requested in moles, you are finished.
Wanted in grams
continue to Step 7
Slide12Steps to Solve Stoichiometric Problems.
How many grams of silver sulfate would be produced from the reaction of 35.0 g of silver nitrate with an excess of magnesium sulfate?
7) If the
wanted
is requested in grams, multiply by the molar mass.
0.103
mol
Ag
2
SO
4
x 311.9 g/
mol
=
32.13 g Ag
2
SO
4