1. 1 Dozen Eggs =
________eggs.
1 Ream of Paper =
_______ sheets of paper.

2. If you think I’m Wait till you watch this…

3. mole and is abbreviated mol.
The Mole
Scientists needed a unit to bridge between the invisible world of atoms and macroscopic world of materials and objects. This unit is called a
mole and is abbreviated mol.
A mole is a fundamental SI unit used to measure the amount of a substance.

4. A mole IS A COLLECTION OF 6.02 x 1023 PARTICLES
Particles can include:
Atoms
Molecules
Compounds

5. Why use the mole?
The mole is used because there is exactly 1 mole of atoms in the atomic mass of an element when that mass is expressed in grams.
Molar mass for all purposes is the same as the atomic mass.
So 1 mole of C-12 , or 6.02 x 1023 atoms, has a mass of g.

6. Who is Avogadro?
The number is named after Amedeo Avogadro because his ideas were crucial to the early development of chemistry.

7. Practice finding molar mass!
1 mole of any element is equivalent to it’s molar mass.
H = g = 1 mole
O2 = 16.0 x 2 = 32.0 g = 1 mole
H2SO4 = g = 1 mole

8. How many moles are in 90.0 g of water?
Formula of water: H2O
Molar mass of water: g = 1 mole
Equation: g x 1 mole = moles
18 g
Answer: 5 moles

9. How many grams are in 6.1 moles of NaCl?
Molar mass:
1 Na x g =
1 Cl x g =
Equation:
6 moles NaCl x gNaCl = grams
1 mol NaCl
Answer with Sig Figs: 360 grams NaCl

10. How many grams are in 0.251 moles of HF?
Molar mass:
1 H x g =
1 F x g =
Equation:
0.251 moles HF x g HF = grams
1 mol HF
Answer with Sig Figs: 5.02 g HF

11. How many molecules are in 0.25 moles of water?
Formula of water: H2O
Conversion factors needed:
1 mole H2O = 18 g H2O & 1 mole = 6.02 x 1023 particles
Equation:
0.25 moles H2O x x 1023 particles =
1 mol H2O
Answer with sig figs: 1.5 x 1023 particles H2O

12. How many moles are in 5.23 x 1020 molecules of MgS?
Conversion factor needed:
1 mole = 6.02 x 1023 particles
Equation:
5.23 x 1020 part MgS x mole MgS =
6.02 x 1023 part MgS
Answer with Sig Figs = mol MgS

13. How many molecules are in 10.0 g of NF3?
Molar mass: 71.0 g
Equations:
10.0 g NF3 x mole NF3 x x 1023 part NF3
71.0 g NF mole NF3
Answer with sig figs: x 1022 part NF3

14. How many grams does 1.80 X 1024 molecules of Cu(OH)2 weigh?
Molar Mass: g
Equations:
1.80 X 1024 part Cu(OH)2 x mole Cu(OH) x g Cu(OH)2
6.02 x 1023 part Cu(OH) mol Cu(OH)2
Answer with sig figs: g Cu(OH)2