Stoichiometry
Moles and Molar mass
How Big is a Mole?
One mole of marbles would cover the entire Earth
(oceans included) for a depth of two miles.
One mole of $1 bills stacked
one on top of another would
reach from the Sun to Pluto
and back 7.5 million times.
It would take light 9500 years to travel from the bottom
to the top of a stack of 1 mole of $1 bills.
Amedeo
Avogadro
?
quadrillions
thousands
trillions
billions
millions
1 mole = 602213673600000000000000
or 6.022 x 1023
Welcome to Mole Island
1 mol = molar mass
1 mole = 22.4 L
@ STP
1 mol =
6.02 x 1023 particles
Stoichiometry Island Diagram
Known
Unknown
Substance A
Substance B
M
Mass
Mass Mountain
Mass
Mole Island
Liter Lagoon
V
Volume
Mole
Mole
Volume
Particles
Particles
P
Particle Place
Stoichiometry Island Diagram
Mass, Volume, Mole Relationship
Formation of Ammonia
Example: What is the number of moles of 14 g Li? (Li:7)
Example: What is the mass of 0.1 mole Ca? (Ca:40)
Example: Calculate the mole number of each of the followings.
a) 13.7g Ba (Ba:137)
b) 10.4 g Cr (Cr:52)
c) 635 g Cu (Cu:63.5)
d) 12 g Mg (Mg:24)
Example: Calculate the mass of each of the following.
a) 0.1 mole Na (Na:23)
b) 0.5 mole Be (Be:9)
c) 2 mole K (K:39)
d) 1.5 mole Fe (Fe:56)
Molecular weight
Example 1: Calculate the molar mass of each of the following.
a) H2O
b) P4
c) CaCl2
d) Na2CO3
e) C2H5OH
f) Al(OH)3
g) NH4NO3
h) H2SO4
i)Ca(OH)2
j) KClO4
k) H3PO4
l) N2O5
m) CaCO3
n) Ca3(PO4)2
Example2: How many moles are 8.8 g of CO2 gas?
Example 3: How many grams are 0.015 moles of Cl2 gas?
Example 4: How many moles are there in 10.26 g of Al2(SO4)3?
1)Calculate the molar mass of
Carbon dioxide
2) How many moles are there in 62.5 grams
of NaHCO3
3) Calculate the molar mass of nitrogen
trioxide
4) Calculate the molar mass of acetic acid
CH3COOH
5) Calculate the number of moles of nitrogen
trioxide in 67.8 grams
6) Calculate the number of grams in 2.5
moles of acetic acid
7)Calculate the number of moles in 36.2 g of
acetic acid
Real life Stoichiometry
Air Bag Design
• Exact quantity of nitrogen gas must be
produced in an instant.
• Use a catalyst to speed up the reaction
2 NaN3(s)  2 Na(s) + 3 N2(g)
6 Na(s) + Fe2O3(s)  3 Na2O(s) + 2 Fe (s)
Rocket Fuel
The compound diborane (B2H6) was at one time
considered for use as a rocket fuel. How many grams
of liquid oxygen would a rocket have to carry to burn
10 kg of diborane completely?
(The products are B2O3 and H2O).
Chemical equation
B2H6 + O2  B2O3 + H2O
Balanced chemical equation B2H6 + 3 O2  B2O3 + 3 H2O
Water in Space
In the space shuttle, the CO2 that the crew exhales is removed from the
air by a reaction within canisters of lithium hydroxide. On average, each
astronaut exhales about 20.0 mol of CO2 daily. What volume of water will
be produced when this amount of CO2 reacts with an excess of LiOH?
(Hint: The density of water is about 1.00 g/mL.)
CO2(g) + 2 LiOH(s)  Li2CO3(aq) + H2O(l)
20.0 mol
excess
xg
X mL H2O = 20.0 mol CO2 (1 mol H2O) (18 g H2O) (1 mL H2O)
(1 mol CO2) (1 mol H2O) (1 g H2O)
X = 360 mL H2O