Moles, Units, and
Conversion Factors
Presented by:
Center for Teaching and Learning
and
Daniel Fox
Why do we measure?
• standardize
• compare
• quantify
Examples of measurement
• Speed- 100 MPH
• Cooking- 4 cups flour
• Building- 8 foot walls
• Weight- lbs, g, kg, etc.
• Money- dollars, euros, yen
• Atoms- (??!!)
English Measurement
System
• Length:
• 12 inches (in) = 1 foot (ft)
3 feet = 1 yard (yd)
5280 feet = 1 mile (mi)
• Capacity:
• 3 teaspoons (tsp) = 1 tablespoon (tbsp)
16 tbsp = 1 cup (c)
8 ounces (oz) = 1 c
2 c = 1 pint (pt)
2 pt = 1 quart (qt)
4 qt = 1 gallon (gal)
• Weight:
• 16 ounces (oz) = 1 pound (lb)
2000 lb = 1 ton
http://regentsprep.org/Regents/math/meteng/LesEng.htm
Metric System of
Measurement
• Length - meters
• Volume- Liters
• Mass - grams
• Time - seconds
English-Metric Conversions
http://www.its.dot.gov/transit_dev/BusSignage/images/conversionFactors.gif
Scientific Notation
1,540,000,000,000 =
0.00000000000154 =
Write these in scientific notation:
65,800,000 =
0.125
=
12
1.54 X 10
-12
1.54 X 10
7
6.58 X 10
-1
1.25 X 10
Metric to metric conversions
0
109
106
103
10-1
10-2
10-3
10-6
10-9
10
Giga-(G) Mega-(M) kilo-(k) m deci-(d) centi-(c) milli-(m) micro-(µ) nano-(n)
Larger Measurements
g
L
s
Smaller Measurements
The mol
• Avagadro’s Number
23
6.02 X 10 = 1 mol
• Used as a ratio to compare different
atomic elements
Metric to Moles
• Write this:
mass
mols
molar
mass
Moles to # Atoms
• Write this:
#Atoms
mols
Avagadro’s
Number
6.02 X 1023
mols Example
• How many mols of are in 5g of
carbon?
5g carbon =
12 g/mol
0.417 mols of carbon
• How many moles of oxygen are in 12
g of CO2?
• 12g CO2 X 2 atoms O
=~0.55mols
44 g/mol 1 molecule CO2
#Atoms example
• How many atoms of Cl are in 0.43 mols
of NaCl?
23
23
0.43mols (6.02 X 10 ) = 2.59 X10 atoms
• How many atoms of Na are in 3g of
NaCl?
23
23
3g NaCl (6.02 X 10 ) = 3.11 X 10 atoms
58 g/mol
Molarity (M)
• Represents concentration of moles in
a solution
• Measured in moles/Liter
• Ex:
• A 1 Molar solution of NaCl:
1 mol NaCl
1 L solution
Applications
• Moles and molarity are used to:
– Determine amount of substance needed
– Calculate limiting reactants
– Compare different elements and
compounds on a standard scale
Application question #1
• How many grams of NaCl are
required to make 500mL of a 2.0M
solution?
2.0 moles/liter (0.5L)= 1mol NaCl
1mol NaCl(58 g/mol) = 58 g NaCl
Application question #2
• What is the molarity of 4g CaCl2
dissolved into 800mL of solution?
4g CaCl2 = .036mols CaCl2
110 g/mol
.036mols= 0.045M solution
0.8L
Application question #3
• How many mols of HCl are required
to make 600mL of a 1.5M solution?
1.5mol/liter (0.6L) = 0.9 mols
Happy Halloween!