1. 6.1 The Mole Obj 1 a-c, 2
Chemistry

2. Essential Questions What is a mole and how is it used?
What is formula mass?
What is molar mass?
How do you find molar/formula mass?

3. Measuring (don’t need to write)
How do we measure eggs or milk?
Why do you think there are different ways of counting something like eggs or paper?
What unit of counting do you think chemists use when talking about atoms?

4. Avogadro's Number (don’t need to write)
Named for Amadeo Avogadro or
6.02x1023

5. The Mole
Chemists use the mole to count the number of particles or atoms.
Chemists use the mole like bakers use a dozen.
One mole equals 6.02 x 1023 particles (Avogadro's Number)
The abbreviation for mole is mol

6. The Mole (cont) The mole is the same for all representative particles.
Representative particle is a substance like atoms, molecules, or formula units.
Molecule: two or more nonmetals (metalloids)
Formula unit: metal and nonmetals
Atom: single atom no subscripts

7. The Mole (cont) 1 mole NaCl= 6.02 x 1023 formula units NaCl
1 mole K = 6.02 x 1023 atoms K
1 mole H2O = 6.02 x 1023 molecules H2O

8. Mole (cont) Find the number of particles for the following:
1.05 mol NH3
Ans: 6.32x1023 molecules NH3
3.0 mol H2
Ans: 1.8x1024 molecules H2
0.768 mol NaCl
Ans: 4.62 x1023 formula units NaCl
5.43x103 mol Cr
Ans: 3.27x1027 atoms Cr

9. Mole (cont) Find the moles for the following
2.4 x 1023 formula units LiO
Ans: 0.40 mol LiO
9.57 x 1021 molecules HCl
5.84 x 1025 atoms Na

10. Chemical Measurements
Atoms have small mass (x10-23g)
Special unit to measure atomic mass
ATOMIC MASS UNIT (amu)
Based on carbon-12
1 amu = 1/12 carbon-12 atoms mass
Find the atomic mass of each atom
Mass of O
amu
Mass of Fe
amu
Mass of C
amu

11. Mass of a Compound
FORMULA MASS – sum of the atomic masses in a compound
What is the mass of one molecule of water?
H2O – 2 hydrogen atoms and 1 oxygen
2 (1.01 amu) + 1 (16.00 amu) = amu
Find the mass of C2H3O2
C: 2 atoms x amu = amu
H: 3 atoms x 1.01 amu = amu
0: 2 atoms x amu = amu
Total = amu
Find the mass of Sr(NO3)2

12. Molar Mass Moles of different substances have different weights
Mass of 1 mole of something = its MOLAR MASS
Molar mass = atomic/formula mass in grams

13. Molar Mass (cont) Zinc Carbon dioxide Find the molar mass of Fe3(PO4)2
Atomic mass = amu
Molar mass = g
Carbon dioxide
Formula mass = amu
Molar mass = g
Find the molar mass of Fe3(PO4)2

14. Essential Questions What is a mole and how is it used?
What is formula mass?
What is molar mass?
How do you find molar/formula mass?

15. 6.1 Tracked Assignment
MUST SHOW WORK to receive credit on calculations
P 296 #10-13,15
P 315 #48,50-54