What is . . . What is . . .

the number of carbon atoms in 12 the number of carbon atoms in 12 grams of carbon?grams of carbon?

the number of oxygen atoms in 16 the number of oxygen atoms in 16 grams of oxygen?grams of oxygen?

the number of Hthe number of H22O molecules in O molecules in 18grams of water?18grams of water?

The MoleThe Mole

Avogadro’s numberAvogadro’s number

1 mole = 6.02 x 101 mole = 6.02 x 102323 particles particles

How big is a Avogadro’s How big is a Avogadro’s number?number?

If we stack 6.02 x 10If we stack 6.02 x 102323 pennies on top of pennies on top of one another, the stack of pennies could one another, the stack of pennies could reach the sun and back almost 500 million reach the sun and back almost 500 million times! times!

A.N. of marbles spread over the surface of A.N. of marbles spread over the surface of the earth would produce a layer of the earth would produce a layer of marbles about 50 miles thick.marbles about 50 miles thick.

If the world’s entire population of 6.5 If the world’s entire population of 6.5 billion people, counting at the rate of one billion people, counting at the rate of one per second, collectively counted to AN, it per second, collectively counted to AN, it would take 3 million years.would take 3 million years.

One mole of any atom is the One mole of any atom is the atomic mass of that atom, atomic mass of that atom,

expressed in grams.expressed in grams. 1 mole Fe = 55.847 grams1 mole Fe = 55.847 grams

1 mole H1 mole H22 = 2.016 grams = 2.016 grams

1 mole CO1 mole CO22 = 12 + 16 + 16 = 44 grams = 12 + 16 + 16 = 44 grams

Called “molar mass”Called “molar mass”

These equivalences can be These equivalences can be used as conversion factorsused as conversion factors

What is the mass in grams of 3.50 What is the mass in grams of 3.50 moles of copper atoms? moles of copper atoms?

3.50 moles x 3.50 moles x 63.546g63.546g== 222 g Cu 222 g Cu 1 mole1 mole How many moles are in 6.195 g of How many moles are in 6.195 g of

phosphorus?phosphorus?

6.195g x 6.195g x 1 mole1 mole== 0.2000 mole 0.2000 mole 30.97 g30.97 g

How many grams are in 2.2mol How many grams are in 2.2mol of NaCl?of NaCl?

2.2mol x 2.2mol x 58.5g58.5g == 128.7g 128.7g

1 mol1 mol

How many moles are in 5.78g of NaCl?How many moles are in 5.78g of NaCl?

5.78g x 5.78g x 1 mol1 mol == .0988mol .0988mol

58.5g58.5g

How many moles is 1.20 x 10How many moles is 1.20 x 102323 atoms of atoms of Zn?Zn?

(1.20 x 10(1.20 x 102323 atoms) atoms)xx

= .199 moles= .199 moles

What is the mass (in grams) of 1.20 x 10What is the mass (in grams) of 1.20 x 102323 atoms of zinc?atoms of zinc?

.199 moles x .199 moles x

= 13.0 g= 13.0 g

atomsx

mole231002.6

1

mole

g

1

39.65

How many atoms are in 0.750 grams Zn?How many atoms are in 0.750 grams Zn?

0.750 g x x 0.750 g x x

= 6.90 x 10= 6.90 x 102121 atoms atoms

g

mole

39.65

1mole

atomsx

1

1002.6 23