Chemistry Lesson 10.1

“The Mole”

I. Measuring Matter

A. 3 ways… 1. counting (#’s) 2. mass (gram, pound…) 3. volume (liter, gallon…) B. Units of measurement… 1. pair = 2 2. dozen = 12 3. ream = 500

I. What is a mole?

A. Def – the S.I. unit that measures an amount or quantity.

1. similar to others: dozen, ream, bakers dozen, gross, hour, day… B.

1 mole = 6.02 x 10 23 particles

1. called Avogadro’s number 2. Usually refers to atoms, molecules, or formula units (Fe, H 2 O, CaCl 2 )

C. Why such a big number?

1. Atoms are microscopic 2. 602,000,000,000,000,000,000,000 3. We need to be precise in chemistry

D. Problems 1. How many moles of iron do you have with 2.41 x 10 24 atoms?

= 4.00 moles of iron 2. I have 3.3 x 10 22 formula units of NaCl. How many moles is this?

=0.055 moles of NaCl 3. I have 9.76 x 10 25 many moles is this?

molecules of N 2 . How =162 moles

4. How many molecules are in 2.12 mol of propane (C 3 H 8 )?

2.12 mol x (6.02 x 10 23 ) propane molecules 1 =1.28 x 10 24 1 mol propane molecules 5. How many atoms of propane are found in 1.28 x 10 24 molecules of propane?

1.28 x 10 24 molecules x 11 atoms 1 =1.41 x 10 25 atoms 1 molecule (C 3 H 2 )

7. With a partner create a question similar to others used today and answer it. Then write the same question down and trade it with another group. Grade it when they are done.

Assignment 7.1

1.

2.

3.

4.

5.

How many atoms are in 4.10 mol of C 6 H 12 O 6 ?

5.92 x 10 25 atoms How many molecules are in 0.750 mol of H 2 O ?

4.52 x 10 23 molecules How many C atoms are in 0.890 mol of C 6 H 12 O 6 ?

3.21 x 10 24 Carbon atoms How many H atoms are in 1.23 mol of C 6 H 12 O 6 ?

8.89 x 10 24 Hydrogen atoms How many mol are found in 6.02 x 10 27 molecules of H 2 O? 1.00 x 10 4 mol of water

II. How much does a mole weigh?

A. Gram atomic mass (single elements) 1. Def – how much 1 mole of an element weighs in grams.

2. Ex: Carbon = 12.01 g 3. Others: P = 30.97

Fe = 55.85

K = Ar = 39.10

39.95

Ag = Li = 107.87

6.94

B. Gram Molecular Mass 1. Def – the mass of one mole of a molecular compound.

2. Use atomic values and add together = GMM 3. Ex: SO 3 S = 32.06

O = 16.00 (3) 32.06 + 48.00 = 80.06 g

4. Examples PO 4 94.97

H 2 O 18.02

PCl 3 137.32

C 8 H 18 114.26

SO 4 96.06

N 2 O 5 108.02

C. Gram Formula Mass 1. Def – the mass of one mole of an ionic compound.

2. Just like GMM 3. Ex: NaCl Na = 22.99

Cl = 35.45

22.99 + 35.45 = 58.44

4. Examples CaI 2 293.88

Li 3 N 34.83

Na 3 PO AlCl 3 4 163.94

133.33

Fe 2 O 3 159.70

Al(OH) 3 78.01

Assignment: Read 10.2 for Thursday.