Unit 7 Notes Part 2

Equivalences to Conversion factors

An equivalence is a when two numbers equal each other. Such as:

●1 dollar = 4 quarters

●1 dozen eggs = 12 eggs

●1 mole A = # g A

●1 mole A = 6.022 x 10²³ atoms/molecules/formula units A

Equivalences to Conversion factors

An equivalence is a when two numbers equal each other. Such as:

●1 dollar = 4 quarters

●1 dozen eggs = 12 eggs

●1 mole A = # g A

●1 mole A = 6.022 x 10²³ atoms/molecules/formula units A

Conversion Factors take equivalences and make them into fractions.

1 mole C = 12.01 g C

1 mole C = 6.022 x 10²³ atoms C

1 mole C

or

12.01 g C

1 mole C

or

6.022 x 10²³ atoms C

12.01 g C

1 mole C

6.022 x 1023 atoms C

1 mole C

Relating Mass to Moles to # of Atoms using Dimensional Analysis

How do we convert among particles, moles and grams?
ALWAYS START WITH WHAT _________ IS GIVEN.

●There are 6.23 moles of Al.

○How many grams of Al are there?

○How many molecules?

●There are 111.7 g of Fe.

○How many atoms?

Relating Mass to Moles to # of Atoms using Dimensional Analysis

How do we convert among particles, moles and grams?
ALWAYS START WITH WHAT NUMBER IS GIVEN.

●There are 6.23 moles of Al.

○How many grams of Al are there?
6.23 mol Al x 26.98 g Al= 168 g Al

1

1 mole Al

Relating Mass to Moles to # of Atoms using Dimensional Analysis

How do we convert among particles, moles and grams?
ALWAYS START WITH WHAT NUMBER IS GIVEN.

●There are 6.23 moles of Al.

○How many grams of Al are there?
6.23 mol Al x 26.98 g Al= 168 g Al

1

1 mole Al

○How many molecules?
6.23 mol Al x 6.022 x 10²³ molecules Al= 37.5 x 10²³ = 3.75 x 10²⁴ molecules Al

1

1 mole Al

●Must fix the scientific notation!

●Apply significant figures!

●Give units!

Relating Mass to Moles to # of Atoms using Dimensional Analysis

How do we convert among particles, moles and grams?
ALWAYS START WITH WHAT NUMBER IS GIVEN.

●There are 6.23 moles of Al.

○How many grams of Al are there?
6.23 mol Al x 26.98 g Al= 168 g Al

1

1 mole Al

○How many molecules?
6.23 mol Al x 6.022 x 10²³ molecules Al= 37.5 x 10²³ = 3.75 x 10²⁴ molecules Al

1

1 mole Al

●There are 111.7 g of Fe.

○How many atoms?
111.7 g Fe x 1 mole Fe x 6.022 x 10²³ atoms Fe= 12.04 x 10²³ = 1.204 x 10²⁴ atoms

1

55.85 g Fe

1 mole Fe

1 mole A = # g A
1 mole A = 6.022 x 10²³

atoms
molecules
formula units

A

●Must fix the scientific notation!

●Apply significant figures!

●Give units!