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 the definition of density. If you rearrange this equation by multiplying each side of the equation by the volume, you get: (Density)(Volume)=Mass. Divide each side by the density to get: Volume=Mass/Density. Now just plug everything in: