The Mole Concept

How can words be used to represent numbers? One example is the word “gross”. If you have a gross of something, you have 12 dozen or 144 items. Can you think of any other words that are used to represent specific numbers?

Dozen=12

Pair=2

Ream=500

Baker’s Dozen = 13

Quartet = 4

What is a mole? Chemists must work with large groups of atoms due to their small size just as bakers work with groups of 12. Chemists called their group a mole (just as bakers call their group a dozen). How many objects make up a mole? A mole = 602,000,000,000,000,000,000,000 or 6.02 x 1023

How large is 6.02 x 1023? A mole of paperclips hooked together in a chain would circle the earth 50 trillion times. A mole of marshmallows would make a 12 mile thick layer covering the entire face of the earth. A mole of popcorn kernels could cover the USA and be 5 miles deep. If you could spend 1 billion dollars a second, it would take you 19 million years to spend a mole of dollar bills. If you could count atoms at a rate of 1 million a second, it would take 20 billion years to count a mole of them.

Moles of Substances Count the number of beans in your bag. Compare with the person sitting next to you. What do your samples have in common? What is different about your samples? How many dozen beans are in your bag? Observe the samples of zinc, aluminum, copper, carbon, and sulfur. What do the samples have in common? What is different about the samples? How is the volume different if the number of particles in each is the same?

12 atoms of carbon is one pair dozen mole ream 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

If I have 1 mole of apples, I have how many? 10 12 500 1 x 106 6.02 x 10 23 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

2 dozen eggs is equal to how many? 10 2 24 100 12.04 x 1023 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

½ a mole of aluminum atoms is how many? 10 0.5 6 3.01 x 10 23 3.01 x 10 12 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

18.06 x 1023 molecules of water is how many moles? 1.5 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Why is a mole = 6.02 x 1023? What is the mass of 1 carbon atom? 12 amu (12 atomic mass units) The atomic mass scale is a relative scale based on the carbon atom. The masses of all other atoms are based on how their masses compare to carbon’s. For example, magnesium is twice as heavy as a carbon atom. What is its mass? 24 amu Hydrogen was discovered to be 1/12 the mass of carbon, so its mass is 1 amu. A chlorine atom is approximately 3 times as heavy as a carbon atom so its mass is approximately 36 amu.

Why is a mole = 6.02 x 1023? In the lab, scientists measure the amount of matter in terms of grams. Therefore, chemists wanted to know how many atoms of carbon would be needed to have a mass of 12 g. A professor by the name of Amadeo Avogadro determined this number to be 6.02 x 1023. This number is now referred to as Avogadro’s number.

How can the concept of a mole be used to count atoms? 1 mole of carbon = 6.02 x 1023 atoms of carbon = 12 grams of carbon 1 mole of hydrogen = 6.02 x 1023 atoms of hydrogen= 1 gram of hydrogen 1 mole of aluminum = 6.02 x 1023 atoms = 27 grams

How can the concept of a mole be used to count atoms? 2 moles of carbon = 12.04 x 1023 atoms of carbon = 24 grams of carbon ½ a mole of carbon = 3.01 x 1023 atoms of carbon= 6 grams of carbon 3 moles of carbon = 18.06 x 1023 atoms = 36 grams 1.5 moles of carbon = 9.03 x 1023 atoms = 18 grams

1 mole of sodium = ___ grams. 10 11 23 6.02 x 10 23 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

2 moles of oxygen = ___ atoms. 10 2 16 32 12.04 x 1023 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

If I have 2 grams of hydrogen, I have ___ atoms. 10 2 3.01 x 1023 6.02 x 1023 12.04 x 1023 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

The mole concept and compounds 1 dozen of water molecules is how many? 12 How many molecules are in 1 mole of water (H20)? 6.02 x 1023 What is the mass of 1 molecule of water? 18 amu What is the mass of 1 mole of water? 18 grams How many molecules are in 2 moles of water? 12.04 x 10 23 What is the mass of 2 moles of water? 36 grams

1 molecule of carbon dioxide has a mass of 10 28 amu 28 grams 44 amu 44 grams 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

1 mole of carbon dioxide is 10 28 amu 28 grams 44 amu 44 grams 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

2 moles of carbon dioxide is ___ molecules. 10 44 88 6.02 x 10 23 12.04 x 1023 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

0.5 moles of carbon dioxide is ___ grams. 10 22 44 3.01 x 10 23 6.02 x 1023 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30