Answer: the amount of a substance that contains 6.02 x 1023 respective particles of that
substance
Avogadro’s number: 6.02 x 1023
Molar Mass: the mass of one mole of an element
CONVERSION FACTORS:
1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)
Try:
1. How many atoms are in 6.5 moles of zinc?
6.5 moles 6.02 x 1023 atoms = 3.9 x 1024 atoms
1 mole
2. How many moles of argon are in a sample containing 2.4 x 1024 atoms of argon?
2.4 x 1024 atoms of argon 1 mole = 4.0 mol
6.02 x 1023 atoms
3. How many moles are in 2.5g of lithium?
2.5 grams Li 1 mole = 0.36 mol
6.9 g
4. Find the mass of 4.8moles of iron.
4.8 moles 55.8 g = 267.84 g = 270g
1 mole
MOLE PARTICLES
(ATOM)
MASS
(g)
1 mole = molar
mass
(look it up on
the PT!)
1 mole =
6.02 x 1023
atoms
1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)
Two Step Problems:
1. What is the mass of 2.25 x 1025 atoms of lead?
2.25 x 1025 atoms of lead 1 mole 207.2g = 7744.19g = 7740g
6.02 x 1023 atoms 1 mole
2. How many atoms are in 10.0g of gold?
10 g gold 1 mole 6.02 x 1023 atoms = 3.06 x 1022 atoms
197.0g 1 mole
PRACTICE PROBLEMS:
1. How many moles are equal to 625g of copper?
625g of copper 1 mol = 9.77 mol Cu
64 g Cu
2. How many moles of barium are in a sample containing 4.25 x 1026 atoms of barium?
4.25 x 1026 atoms of barium 1 mol = 706 mol
6.02 x 1023 atoms
3. Convert 2.35 moles of carbon to atoms.
2.35 moles 6.02 x 1023 atoms = 1.41 x 1024 atoms
1 mole
4. How many atoms are in 4.0g of potassium?
4.0 g 1 mole 6.02 x 1023 atoms = 6.2 x 1022 atoms
39.1 g 1 mole
1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g)
5. Convert 9500g of iron to number of atoms in the sample.
9500 g Fe 1 mole 6.02 x 1023 atoms = 1.0 x 1026 atoms
55.8g 1 mole
6. What is the mass of 0.250 moles of aluminum?
0.250 moles 27.0g = 6.75 g Al
1 mole
7. How many grams is equal to 3.48 x 1022 atoms of tin?
3.48 x 1022 atoms 1 mole 118.7g = 6.86 g Sn
6.02 x 1023 atoms 1 mole
8. What is the mass of 4.48 x 1021 atoms of magnesium?
4.48 x 1021 atoms 1 mole 24.3g = 0.181 g Mg or 1.8 x 10-1
6.02 x 1023 atoms 1 mole
9. How many moles is 2.50kg of lead?
2.50kg 1000 g 1 mol = 12.1 mol
1 kg 207.2 g
10.Find the mass, in cg, of 3.25 x 1021 atoms of lithium.
3.25 x 1021 atoms 1 mol 6.9g 100cg = 3.7
Explanation:
). This is because the oxidation number of pure elements (whether alone as an atom or combined with other atoms of the same element such as the diatomic nitrogen) is always zero. 
) compounds where nitrogen has an oxidation number of zero.