Avogadro

1
Avogadros Number

• The of 12C atoms in 12 grams of Carbon.
• 6.02 x 1023

2
Mole

• A mole of any substance represents an Avogadros
  number of particles.
• 1 mole (or mol) 6.02x1023 particles

3
Molar Mass

• The gram mass of one mole of the substance.
• Numerically equal to the atomic mass
• Unit grams per mole

4
Mole problem 1

• How many moles of glucose are in 100 grams?
• How many molecules?
• How many carbon atoms?

5
Mole Problem 2

• What is the gram mass of a sample of glucose that
  contains 2.5x1024 H atoms?

6
Predicting Empirical Formulas using the mole

• What is the empirical formula for a substance
  composed of 0.0130 mol C, 0.0390 mol H, 0.0065
  mol O?

7
Predicting Empirical Formulas using the mole

• What is the empirical formula for a substance
  composed 11.66 g Fe and 5.01g of O?

8
Predicting Empirical Formulas using the mole

• What is the empirical formula for a substance
  composed 40.0 C, 6.7 H, 53.3 O?

9
Predicting Molecular Formulas using the mole

• What is the molecular formula for a substance
  composed 75.69 C, 8.80 H, 15.51 O and has a
  molar mass of about 206 g/mol?