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Slide 1 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
> INTRODUCTION
How do we measure the amount of something?
MA
By mass By volume By count
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
Slide 2 of 43
What is a Mole?
Measuring amounts of small particles Chemists measure the amount of a substance using a unit called mole.
10.1
Slide 3 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
> What is a Mole?
How many particles are there in a mole?
As one dozen contains 12 units, one mole of a substance contains 6.02 × 1023 representative particles. This number is called Avogadro’s number. 1. How many cookies in a mole of cookies?
6.02 x 1023
2. How many cookies in half a mole of cookies? 3.01 x 1023
10.1
Slide 4 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
Representative particle: term for particle that is being counted.
Representative particles can be atoms, ions, molecules, and formula unit (ionic compounds).
© Copyright Pearson Prentice Hall
SAMPLE PROBLEM
Slide 5 of 43
What is a Mole?
Converting Moles to Number of Particles
Practice: How many atoms are there in 3 moles of atoms of Neon?
1 mole = 6.02 x 1023 particles
© Copyright Pearson Prentice Hall
SAMPLE PROBLEM
Slide 6 of 43
What is a Mole?
Practice: How many moles are there in 12.04 x 10 23 atoms of sodium?
10.1
Converting Particles to Number of Moles
1 mole = 6.02 x 1023 particles
Slide 7 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
> The Mass of a Mole of an Element
The atomic mass of an element expressed in grams is the mass of a mole of the element.
AKA: molar mass.
The unit of molar mass is g/mol.
10.1
Slide 8 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
> The Mass of a Mole of an Element
One molar mass of carbon, sulfur, mercury, and iron are shown.
10.1
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
Slide 9 of 43
The Mass of a Mole of a Compound
The Mass of a Mole of a Compound
Molar Mass (mass of one mole) :
Add up the molar masses of each element in a compound.
10.1
Slide 10 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
> The Mass of a Mole of a Compound
32.07 g + 16.00 g +16.00 g +16.00 g = 80.07 g
1 mole of SO3 has a mass of 80.07 g.
Another way to say it: the molar mass of SO3 is 80.07 g/mole
10.1
Slide 11 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
What is the molar mass of the following?
PCl3
(NH4)2SO4
Slide 12 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
> 10.5
Converting moles to mass
Practice: How many grams are there in 2 moles of sulfur trioxide (SO3)?
2 mole SO3 80.07 g SO3 1 mole SO3
= 160.14 g SO3
1 mole = molar mass of a substance
Slide 13 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
> 10.5
Converting moles to mass
Practice: How many moles are there in 90 g of sulfur trioxide (SO3)?
90 g SO3 1 mole SO3 80.07 g SO3
= 1.12 mole SO3
1 mole = molar mass of a substance
Slide 14 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
How many moles in 3.6 g of C2H4Br2?
How many grams in 0.17 moles of Bi(NO3)2?
A Mole is a Unit
Slide 15 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
Ionic Compounds and Number of Particles:
First, let’s Review ….
What are the products of single replacement? Double replacement?
New ionic compounds are made and their formulas follow the same rules we have been using all along
Slide 16 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
Ca(OH)2 + H2SO4 →
1. Write the ions
2. Identify the type of reaction and therefore the type of products (i.e. double replacement will give two ionic compounds)
3. Write the formula of the products (follow the rules for ionic compounds!)- subscripts
4. Balance the equation with coefficients.
Slide 17 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
Ca(OH)2 + H2SO4 → CaSO4 + 2HOH
How many ions are in calcium hydroxide?
How many ions are in 1 moles of calcium hydroxide?
Slide 18 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
Determining # of ions in an ionic compound…
Pb3(PO4)2 1. Identify ions
Pb2+ PO43-
2. Count # of cations and # of anions. Add them up.
Cations: 3 Anions: 2 Total= 5
Slide 19 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
How many ions are in 1 mole of Pb3(PO4)2 ?
= 3.01 x 1024
ions
6.02 x 1023 compound 5 ions
1 compound
1 mole
1 mole
Slide 20 of 43
© Copyright Pearson Prentice Hall
The Mole: A Measurement of Matter
>
How many ions are in 0.25 mole of Pb3(PO4)2 ?
6.02 x 1023 compound 5 ions
1 compound
0.25 mole
1 mole
= 7.52 x 1023 ions