by mass by volume by count - skyline...

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



>

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

of 43



> 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

of 43



>

Representative particle: term for particle that is being counted.

Representative particles can be atoms, ions, molecules, and formula unit (ionic compounds).


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


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

of 43



> 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

of 43



> The Mass of a Mole of an Element

One molar mass of carbon, sulfur, mercury, and iron are shown.

10.1



>

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

of 43



> 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

of 43



>

What is the molar mass of the following?

PCl3

(NH4)2SO4

of 43



> 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

of 43



> 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

of 43



>

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

of 43



>

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

of 43



>

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.

of 43



>

Ca(OH)2 + H2SO4 → CaSO4 + 2HOH

How many ions are in calcium hydroxide?

How many ions are in 1 moles of calcium hydroxide?

of 43



>

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

of 43



>

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

of 43



>

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

by mass by volume by count - skyline...

Documents