atomic mass the atomic mass is the average mass of an atom

Atomic mass

• The atomic mass is the average mass of an atom.

When using atomic masses make sure to round to at least one decimal place.

What is the atomic mass of actinium (Ac)?

227.0278

227.0

What is the atomic mass of hydrogen (H)?

1.00794

1.0

What is the mass of hydrogen (H2)?

2.0

Vitamin A: C20H30O

• The first of the 13 vitamins to be discovered, it plays a vital role in the growth and repair of body tissues, and is particularly important in maintaining good eyesight and healthy skin, as well as aiding in bone and teeth formation.

• Vitamin A-rich foods include: Liver, sweet potatoes, carrots, mangoes, spinach, cantaloupe, dried apricots, milk, egg yolks, mozzarella cheese.

Determine the Molecular Mass of Vitamin AC20H30O

20 x 12.0 = 240.030 x 1.0 = 30.01 x 16.0 = 16.0 = 286.0 amu

H H2O NaCl

• H is an atom and it would therefore have an atomic mass.

• H2O is a molecule and it would therefore have a molecular mass.

• NaCl is neither an atom or a molecule and would therefore have a formula mass.

Formula Mass

• The formula mass is the mass of an ionic compound.

• An ionic compound is formed from a combination of metals and nonmetals.

• Formula masses are calculated the same as molecular masses.

Determine the Formula Mass of Calcium Phosphate

Ca3(PO4)2

3 x 40.1 = 120.32 x 31.0 = 62.08 x 16.0 = 128.0 = 310.3 amu

Chapter 8: The Mole – Part 1

What is Avogadro’s favorite saying from American History?

The Mole

• A mole is Avogadro’s number of particles, that is 6.02 × 1023 particles.

• 1 mol = Avogadro’s Number

= 6.02 × 1023 particles

How Big is a Mole?

• Where would you need to go to see 1 mole of rice grains?

How Big is a Mole?

• 1 mole of rice grains is more than the number of rice grown since the beginning of time?

How Big is a Mole?• The worlds fastest supercomputer can count the

world’s population in ¼ second. How long would it take this computer to count to 1 mole?

How Big is a Mole?• The worlds fastest supercomputer can count the

world’s population in ¼ second. It would take this computer 1.9 million years to count to 1 mole?

How Big is a Mole?

One mole of marbles would cover the entire Earth (oceans included) for a depth of three miles.

One mole of $100 bills stacked one on top of another would reach from the Sun to Pluto and back 7.5 milliontimes.

It would take light 9500 years to travel from the bottom to the top of a stack of 1 mole of $100 bills.

How Big is a Mole?• Where would you

need to go to see 1 mole of water.

World’s Fastest Super Computervs.

Super Teacher

The Marble Contest

What is the mass in grams of exactly 1 mole of water?

• 1.66 x 10-24 g/amu

1 mol H2O

What is the mass in grams of exactly 1 mole of water?

• 1.66 x 10-24 g/amu

1 mol H2O

mol H2O

6.02 x 1023 H2O molecules

What is the mass in grams of exactly 1 mole of water?

• 1.66 x 10-24 g/amu

1 mol H2O

mol H2O

6.02 x 1023 H2O molecules

molecule H2O

18.0 amu

What is the mass in grams of exactly 1 mole of water?

• 1.66 x 10-24 g/amu

1 mol H2O

mol H2O

6.02 x 1023 H2O molecules

molecule H2O

18.0 amu

amu

1.66 x 10-24 g

What is the mass in grams of exactly 1 mole of water?

• 1.66 x 10-24 g/amu

1 mol H2O

mol H2O

6.02 x 1023 H2O molecules

molecule H2O

18.0 amu

amu

1.66 x 10-24 g

= 18.0 g

1 mol H2O = 18.0g

• This is the gram formula mass of water.

• This is the molar mass of water.

• The gram formula mass (molar mass) is the molecular mass of the substance in grams.

What is the mass of 1 mol sucrose (C12H22O11)

1 mol sucrose (C12H22O11) = 342.0g

• 12 x 12.0 = 144.0

• 22 x 1.0 = 22.0

• 11 x 16.0 = 176.0

gfm = 342.0 g

Homework

• Molecular and Formula Mass Worksheet (due in two days).

• Don’t forget to show your work on your calculations.

Why 6.02 x 1023

• How did scientists come up with such a random number for the mole?

• It’s really not random at all. It is really just based on a ratio that you already know.

• 1.66 x 10-24 g/amu.

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

1 mol C

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

1 mol C 12.0 g C

mol

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

1 mol C 12.0 g C 1 amu

mol 1.66 x 10-24 g

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

1 mol C 12.0 g C 1 amu C atom

mol 1.66 x 10-24 g 12.0 amu

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

1 mol C 12.0 g C 1 amu C atom

mol 1.66 x 10-24 g 12.0 amu

= 6.02 x 1023 C atoms/mol

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

1 mol C 12.0 g C 1 amu C atom

mol 1.66 x 10-24 g 12.0 amu

= 6.02 x 1023 C atoms/mol

Why 6.02 x 1023

• How many atoms are in exactly one mole of carbon?

1

1.66 x 10-24= 6.02 x 1023

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

1 mol H2O

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

1 mol H2O 18.0 g H2O

mol

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

1 mol H2O 18.0 g H2O 1 amu

mol H2O 1.66 x 10-24 g

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

1 mol H2O 18.0 g H2O 1 amu H2O molecule

mol 1.66 x 10-24 g 18.0 amu

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

1 mol H2O 18.0 g H2O 1 amu H2O molecule

mol 1.66 x 10-24 g 18.0 amu

= 6.02 x 1023 H2O molecules/mol

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

1 mol H2O 18.0 g H2O 1 amu H2O molecule

mol 1.66 x 10-24 g 18.0 amu

= 6.02 x 1023 H2O molecules/mol

Why 6.02 x 1023

• How many molecules are in exactly one mole of water?

1

1.66 x 10-24= 6.02 x 1023