2.  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?

8.  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 10 23

9.  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.

10.  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?

11. 10 1. pair 2. dozen 3. mole 4. ream 1234567891011121314151617181920 21222324252627282930

12. 10 1. 12 2. 500 3. 1 x 10 6 4. 6.02 x 10 23 1234567891011121314151617181920 21222324252627282930

13. 10 1. 2 2. 24 3. 100 4. 12.04 x 10 23 1234567891011121314151617181920 21222324252627282930

14. 10 1. 0.5 2. 6 3. 3.01 x 10 23 4. 3.01 x 10 12 1234567891011121314151617181920 21222324252627282930

15. 10 1. 18 2. 23 3. 1.5 4. 3 1234567891011121314151617181920 21222324252627282930

16.  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.

17.  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 10 23.  This number is now referred to as Avogadro’s number.

18.  1 mole of carbon = 6.02 x 10 23 atoms of carbon = 12 grams of carbon  1 mole of hydrogen = 6.02 x 10 23 atoms of hydrogen= 1 gram of hydrogen  1 mole of aluminum = 6.02 x 10 23 atoms = 27 grams

19.  2 moles of carbon = 12.04 x 10 23 atoms of carbon = 24 grams of carbon  ½ a mole of carbon = 3.01 x 10 23 atoms of carbon= 6 grams of carbon  3 moles of carbon = 18.06 x 10 23 atoms = 36 grams  1.5 moles of carbon = 9.03 x 10 23 atoms = 18 grams

20. 10 1. 11 2. 23 3. 6.02 x 10 23 4. 1 1234567891011121314151617181920 21222324252627282930

21. 10 1. 2 2. 16 3. 32 4. 12.04 x 10 23 1234567891011121314151617181920 21222324252627282930

22. 10 1. 2 2. 3.01 x 10 23 3. 6.02 x 10 23 4. 12.04 x 10 23 1234567891011121314151617181920 21222324252627282930

23.  1 dozen of water molecules is how many?  12  How many molecules are in 1 mole of water (H 2 0)?  6.02 x 10 23  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

24. 10 1. 28 amu 2. 28 grams 3. 44 amu 4. 44 grams 1234567891011121314151617181920 21222324252627282930

25. 10 1. 28 amu 2. 28 grams 3. 44 amu 4. 44 grams 1234567891011121314151617181920 21222324252627282930

26. 10 1. 44 2. 88 3. 6.02 x 10 23 4. 12.04 x 10 23 1234567891011121314151617181920 21222324252627282930

27. 1. 22 2. 44 3. 3.01 x 10 23 4. 6.02 x 1023 10 123456789 11121314151617181920 21222324252627282930