Stoichiometry

1
Stoichiometry

• Chapter 12
• Section 1

2
Stoichiometry

• Definition
• measurement of the amount of substances in a
  chemical reaction and how they relate to each
  other
• Avogadros Principle
• Relates the number of particles in a sample of a
  substance to a direct measurement made of that
  substance

3
Stoichiometry

• Mole abbreviated mol
• Unit for the number of atoms, molecules, formula
  units, particles, etc.
• 1 mol 6.02 x 1023 (anything)
• Avogadros constant 6.0221367 x 1023

4
Stoichiometry

• Examples
• 1 mol C 6.02 x 1023 atoms C
• 1 mol CO2 6.02 x 1023 molecules CO2
• 1 mol Na ions 6.02 x 1023 ions Na

5
Stoichiometry

• Molar Mass
• Mass of 1 mol of a pure substance
• Mass of the element from the periodic table
  rounded to the nearest whole number

6
Stoichiometry

• Elements Examples
• Start with moles
• Start with mass

7
Stoichiometry

• Elements Examples Continued
• To get to a final unit of atoms, molecules,
  particles, etc. you must use moles
• Start with moles use Avogadros number
• Start with mass change to mol then use Avogadro

8
Stoichiometry

• Compounds
• Molar Mass
• Element1 atomic mass x atoms value1
• Element2 atomic mass x atoms value2
• Element3 atomic mass x atoms value3
• Sum of all values with the units (g/mol)

9
Stoichiometry

• Compounds Examples
• C2H6O
• C 12 g x 2 24
• H 1 g x 6 6
• O 16 g x 1 16
• 24 6 16 46 g/mol
• CaCl2
• Ca 40 g x 1 40
• Cl 35.5 g x 2 71
• 40 71 111 g/mol

10
Stoichiometry

• Compounds
• Follow the same setup as with an element
• mol to g use the molar mass of compound
• g to mol invert the molar mass of compound