Download Day 14- Stoichiometry 1 Mole and Particle Relationships

The Mole Highway
atoms
atoms
# molecules
or
# formula units
# molecules
or
# formula units
use
NA
use
NA
moles A
use mol
ratio
moles B
use
M
use
M
mass
mass
concentration
concentration
Stoichiometry
The study of number of particles ­ mole ­ mass relationships in chemical reactions.For all stoichiometry questions you should use the MOLE HIGHWAY.
Ex.1
1 lettuce + 2 leeks + 4 tomatoes ­­> 1 salad
Ex.2
N2(g) + 3 H2 (g) ­­­> 2 NH3 (g)
1 particle + 3 particles ­­> 2 particles
5 particle + 15 particles ­­> 10 particles
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p.237#2
2 Fe + 3 Cl2 ­­> 2 FeCl3
a)
? particles Fe
3 particles Cl2
b)
150 particles Fe
c) 1.204 x 1024 particles Fe
? particles FeCl3
? particles FeCl3
1.806 x 1024 particles Cl2
d)
? particles FeCl3
Particle Relationships
N2(g) + 3 H2 (g) ­­­> 2 NH3 (g)
1 particle + 3 particles ­­> 2 particles
1 dozen + 3 dozen ­­> 2 dozen
6.02 x 1023 + 1.81 x 1024 ­­> 1.20 x 1024
1 mol + 3 mol ­­> 2 mol
The coefficients in chemical equations represent particles AND they can also represent moles.
We can express the relationship between numbers of particles by a mole ratio.
1 mol N2
2 mol NH3
Always work with a BALANCED EQUATION!!!
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Mole Relationships
p.238 #4
Try p.238 #5
Sulfur reacts with oxygen to make sulfur trioxide gas. Assuming excess sulfur, how many molecules of sulfur trioxide would me made from 1.33 x 105 molecules of oxygen? 1) Use the MOLE HIGHWAY to plan your steps
molecules O2 molecules SO3
2) Write the BALANCED chemical equation to determine the mole ratio
3) Calculate using unit analysis
= 8.87 x 10 4 molecules of sulfur trioxide would be made
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Homework
p. 237#2
p.238 # 5,6
p.240 # 9,10
Tomorrow­ Stoichiometry Mass Relationships
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