1. relative atomic mass The Mole

2. Atomic mass Mass: A measure of the amount of matter
Atomic Mass: The average mass of all the isotopes of a particular element
Atoms of different elements have different masses

3. Atomic mass
The atomic mass is found by comparing the mass of an atom of an element to the mass of an atom of Carbon-12
Carbon-12 is assigned an atomic mass of exactly u (“u” stands for “unified atomic mass unit”)

4. Atomic mass The mass of one individual atom is extremely small
A large number of atoms is required to provide enough mass to measure its mass
A MOLE is a unit that measures the number of atoms that is equivalent to the atomic mass of a particular element
Or…. The molecule mass of a molecule (we will get there shortly!)

5. Inquiry Questions
Form groups of 3-4, collect a whiteboard and pens and answer following questions
Why does a mole of Carbon -12 weigh EXACTLY g?
Why was carbon the first element assigned a weight?
When you look at the periodic table, why do elements have atomic masses with decimals??

6. Inquiry Questions
Form groups of 3-4, collect a whiteboard and pens and answer following questions
Why does a mole of Carbon -12 weigh EXACTLY g?
Actually, it’s the other way round, Avogadro wanted a mole to be EXACTLY g of carbon. He picked g, because carbon contains 6 protons and 6 neutrons in it’s nucleus.

7. Inquiry Questions
Form groups of 3-4, collect a whiteboard and pens and answer following questions
Why was carbon the first element assigned a weight?
Carbon is the element of LIFE! It held great value in the chemistry community, and is the basis of a major subdivision of Chemistry known as Organic Chemistry.
We will study organic Chemistry in Unit 8!

8. Inquiry Questions
Form groups of 3-4, collect a whiteboard and pens and answer following questions
When you look at the periodic table, why do elements have atomic mass between that have decimals?
Unfortunately, not everything is simple.
As you remember from Science 10 elements have the same number of protons but can have different numbers of neutrons. These atoms of the same element are known as isotopes. The number on the table is a weighted AVERAGE of all the isotopes.

9. What is a unit? Definitive magnitude Examples: 1 dozen = 12 items
1 minute = 60 seconds
1 year = 365 days
Sig Figs are infinite!

10. (do not confuse this with molecules!)
WHAT IS A MOLE?
Avogadro’s Number
x 1023 items per mole
The abbreviation for the unit mole is mol.
(do not confuse this with molecules!)

11. A Mole of Pennies
Please collect the handout from the front of the room
Complete the activity with 1 or 2 neighbours

12. how big is the mole?
If you had Avogadro’s number of unpopped popcorn kernels, and spread them cross the US, the country would be covered in popcorn to a depth of over 14.5 km’s

13. how big is the mole?
If 6.02 x 1023 doughnuts were divided equally among Earth’s 7 billion people, each person would have about 8.6 x 1013 or
(86 trillion) doughnuts

14. how big is the mole?
One mole of paper would make a stack that would reach to the moon more than 80 billion times.

15. how big is the mole?
One mole of seconds is about 19 quadrillion years, or times the age of the earth, or times the age of the universe.

16. how big is the mole?
If you were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole

17. Welcome to the…

18. How many lithium atoms are in 3.2 MOL of lithium?