1. Chapter 8: The Mole Section 8-1: How are atoms counted and measured?

2. Review: Chapter 3 Bonus Point Opportunity! Atomic Theory: All Matter is composed of atoms What is the SI unit for the amount of substance? The Mole Avagadro’s Number 6.022 X 1023 particles/atoms/ions

3. Lesson Overview and Objectives By the end of this lesson you will understand how atoms are counted and measured You will be able to define a mole and what it represents You will be able to recite Avagadro’s number and what it represents You will be able to convert from the number of moles in an element to the number of particles/atoms/ions/etc You will be able to convert from the number of particles/atoms/ions/etc in an element to the number of moles

4. Review: Conversions Math Review If you have 26 meters how many kilometers do you have? What are we looking for? Kilometers How do we set up the conversion so meters cancel? 26 m X 1 km 1 1000 m 26 m X 1 km = 1 1000 m 26 km = .026 km 1000

5. What is a Mole? Elements are made up of atoms - the number of atoms in a small sample of an element is astronomical Scientists needed to find a way to deal with them on a larger scale- so they created a new unit of quantity The mole is: The number of atoms in exactly 12g of carbon-12

6. What Does a Mole Represent? “Is a counting unit used for measuring an amount of a substance” Refer to table 8-1 on page 275 in text Easter Eggs, pennies, spoons

7. What is Avagadro’s Number? Avagadro’s number is the number of particles in a mole 6.022 X 1023 particles in a mole Avagadro’s number is a constant, meaning that it does not change

8. What Does Avagadro's Number Represent? While Avagadro’s number represents the number of particles in a mole, particles has multiple meanings Particles can mean: Atoms, Ions, molecules, electrons, bonds, etc How many atoms are in a mole? 6.022 X 1023 How many Ions are in a mole? 6.022 X 1023 How many molecules are in a mole? 6.022 X 1023

10. Conversion Time: Moles to Atoms Convert 4.2 Moles of He to atoms Convert 3.6 Moles of N to atoms Convert 1.3 Moles of C to ions Convert 2.6 moles of Na to molecules

11. Conversion Time: Atoms to Moles Convert 6.4 X 1023 atoms of S to Moles Convert 8.6 X 1024 atoms of F to Moles Convert 1.3 X 1023 atoms of Si to Moles Convert 4.2 X 1023 ions of Ni to Moles Convert 2.3 X 1023 molecules of C to Moles

12. Wrap-Up When converting atoms/ions/molecules/etc to moles what constant do you use? 6.022 X 1023 What is that constant called? Avagadro’s Number How many ions are in one mole? 6.022 X 1023 Questions?