Chemistry I
Mr. Patel
SWHS

• MUST have a scientific calculator (not graphing)!!!
• Review of Factor-label Method
• The Mole and Particle to Mole Conversion (10.1)
• Molar Mass and Gram to Mole Conversion (10.2)
• Chemical Formula as a Conversion Factor (N/A)
• Solution Concentration (16.2)
• Percent Composition (10.3)
• Empirical and Molecular Formulas (10.3)

• Conversion factor – allows us to convert from one unit to another unit
– Example: 1m = 1000mm, 1 dozen = 12 items
• We use the factor label method to convert
Given New Unit
=
Desired
Quantity
Old Unit
Remember:
Multiply the top
Divide the bottom

• A count refers to a grouping or a word representing a number
– Pair (2), Dozen (12), Ream (500)
• A count is a conversion factor – can convert between a count unit and the number of items
– Ex: 1 dozen egg is the same as 12 actual eggs

Ex: Convert 3 dozen apples to number of apples.
Use the factor-label method.
3 dozen apples 12 apples
1 dozen apples
= 36 apples

• Representative Particle – species present in a particle
– Atoms (elements; ex: Fe atom)
– Molecules (covalent compounds; ex: diatomics)
– Ions (species with a charge; ex: Na 1+ )
– Formula Units (ionic compounds; ex: NaCl)

• The fundamental count in chemistry is the
mole – SI unit for amount
– Very similar to a dozen; represents a number
– Abbreviation: mol
– Contains an Avogadro’s Number of items
– Avogadro’s Number = 6.02 x 10 23

• It is not appropriate to consider only one atom of an element or one formula unit of a compound
– It is easier to group atoms using a large number
– NOTE: 1 mole contains the same number of item…but does not necessarily have the same mass!!!

• Just like a dozen, the mole is a conversion factor!
• We can convert between the unit (mole) and the number of items
• Remember:
– 1 mole X = 6.02 x 10 23 X
– You can substitute any item for the X

Ex: Convert 1 mole of Fe to number of Fe atoms.
Use the factor-label method.
1 mol Fe
6.02 x 10 23 atoms Fe
= 6.02 x 10 23 atoms Fe
1 mol Fe
Math: (1) x (6.02 x 10 23 ) / (1) = 6.02 x 10 23

Ex: Convert 7.8 mol of clipped fingernails to number of clipped fingernails (CF).
Use the factor-label method.
7.8 mol CF
6.02 x 10 23 CF
1 mol CF
= 4.7 x 10 24 CF
Math: (7.8) x (6.02 x 10 23 ) / (1) = 4.7 x 10 24

Ex: Convert 2.1 x 10 9 atoms of Li to moles of Li.
Use the factor-label method.
2.1 x 10 9 atom Li
1 mol Li
6.02 x 10 23 atoms Li
= 3.49 x 10 -15 mol Li
Math: (2.1 x 10 9 ) x (1) / (6.02 x 10 23 ) = 3.49 x 10 -15