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Transcript Slide 1

Stoichiometry
Tutorial
By: Chelsea Cooper
th
8 Period
Begin
Problem
A somewhat antiquated method for preparing chlorine gas involves heating
hydrochloric acid with pyrolusite (manganese dioxide), a common manganese ore.
(Reaction given below.) How many kg of HCl react with 5.69 kg of manganese dioxide?
HCl(aq) + MnO2(s)
H2O(l) + MnCl2 (aq) + Cl2(g)
First you…
Calculate GFM
Find mole to
mole ratio
Balance the
Equation
4 HCl(aq) + MnO2(s)
m(kg) = ?
2 H2O(l) + MnCl2 (aq) + Cl2(g)
m = 5.69 kg
Great! Next you…
Calculate the
GFM
Convert kg into g
That’s it! I’m done!
The GFM of MnO2 is 86.94g.
Now what do you do?
Convert g into kg
Find out how
many moles
5.69kg equals.
Multiply by 4
4 HCl(aq) + MnO2(s)
m
M
=
2 H2O(l) + MnCl2 (aq) + Cl2(g)
5.69kg
= 0.0654kmol MnO2(s)
86.94g/mol
So far so good! Then you…
This is my
answer…
Convert
0.0654kmol into
mol
Multiply
0.0654kmol by 4
4 HCl(aq) + MnO2(s)
2 H2O(l) + MnCl2 (aq) + Cl2(g)
0.0654kmol x 4 = 0.2616kmol MnO2(s)
Find the GFM of HCL
and multiply it by
0.2616kmol
Divide 0.2616
by 2
Now I’m Done!
Answer
36.5g HCl x 0.2616kmol = 9.55kg HCl
Congrats!
Your Stoichiometry skills are
outta this world!!!