1. Unit 4 Toxins the Mole Intro Chemistry

2. Toxins We saw the reaction of certain toxics with chemicals in the human body. We saw the reaction of certain toxics with chemicals in the human body. However, different toxins react in different quantities However, different toxins react in different quantities In this unit, we see how we can calculate quantities of chemicals using the unit: In this unit, we see how we can calculate quantities of chemicals using the unit: THE MOLE!

3. The Mole

4. Counting Units How many is a dozen? How many is a dozen? How many does the word “couple” stand for? How many does the word “couple” stand for? How many sheets are in a ream of paper? How many sheets are in a ream of paper? Answers: 12, 2, 500 Answers: 12, 2, 500

5. Chemist’s “Dozen” Chemists also have a counting unit for a certain number of things Chemists also have a counting unit for a certain number of things A mole = Avogadro’s number of things A mole = Avogadro’s number of things 1 mole = 6.02 x 10 23 things 1 mole = 6.02 x 10 23 things Could be atoms, ions, particles, molecules, etc.Could be atoms, ions, particles, molecules, etc. How big is that number? How big is that number?

6. Sample Problem How many atoms are contained in 4.5 moles of copper? How many atoms are contained in 4.5 moles of copper? How many moles are in 8.3 x 10 24 molecules of water? How many moles are in 8.3 x 10 24 molecules of water? Answers: 2.71 x 10 24 atoms, 13.8 moles Answers: 2.71 x 10 24 atoms, 13.8 moles

7. Masses and Moles If you had a dozen bowling balls and a dozen ping pong balls, which would have more mass? Why? If you had a dozen bowling balls and a dozen ping pong balls, which would have more mass? Why? The bowling balls would have more mass because each individual bowling ball has more mass than a ping pong ball. The bowling balls would have more mass because each individual bowling ball has more mass than a ping pong ball.

8. Mass of Elements and Moles Which would be heavier: a mole of copper or a mole of lead? Why? Which would be heavier: a mole of copper or a mole of lead? Why? A mole of lead would be heavier because an atom of lead is heavier than an atom of copper (64 amu vs. 207 amu) A mole of lead would be heavier because an atom of lead is heavier than an atom of copper (64 amu vs. 207 amu)

9. Carbon-12 and Avogadro’s Number Avogadro’s number is related to the mass of an element, specifically carbon (the isotope carbon-12) Avogadro’s number is related to the mass of an element, specifically carbon (the isotope carbon-12) Used exactly 12 grams of carbon and determined the number of atoms in that sample Used exactly 12 grams of carbon and determined the number of atoms in that sample There are 6.02 x 10 23 atoms in 12 grams of carbon (1 mole) There are 6.02 x 10 23 atoms in 12 grams of carbon (1 mole)

10. Definition of Mole A mole is the amount of matter that contains as many objects (atoms, molecules, etc.) as the number of atoms in exactly 12 g of 12 C. A mole is the amount of matter that contains as many objects (atoms, molecules, etc.) as the number of atoms in exactly 12 g of 12 C. Mole connects amu & gram = “Chemists dozen”Mole connects amu & gram = “Chemists dozen”

11. Molar Mass How do you determine moles if you have a compound? How do you determine moles if you have a compound? What is the mass of 1 mole of NaCl? What is the mass of 1 mole of NaCl? Answer: 58 g/mol Answer: 58 g/mol Molar Mass: the mass of one mole of a substance (element or compound) Molar Mass: the mass of one mole of a substance (element or compound)

12. Sample Problem- molar mass What is the mass of one mole of What is the mass of one mole of water?water? Carbon dioxide?Carbon dioxide? C 6 H 12 O 6 (glucose)C 6 H 12 O 6 (glucose) Ca(NO 3 ) 2Ca(NO 3 ) 2 Answers: 18 g/ mol, 44, 180, 164Answers: 18 g/ mol, 44, 180, 164

13. Sample Problem- moles to mass How many grams of sodium chloride (NaCl) did you use if you put 0.25 moles of it on your French fries? How many grams of sodium chloride (NaCl) did you use if you put 0.25 moles of it on your French fries? Answer: 14.5 g Answer: 14.5 g

14. Sample Problem – mass to moles How many moles of helium are in a balloon that contains 4.5 g of helium? How many moles of helium are in a balloon that contains 4.5 g of helium? Answer: 1.13 moles Answer: 1.13 moles

15. Study Buddy Review What is Avogadro’s Number? What is Avogadro’s Number? What is a mole? What is a mole? What is molar mass? What is molar mass? How do you find the molar mass of a compound? How do you find the molar mass of a compound?