The Mole

Counting Matter

Counting Matter

What are some everyday ways we count matter?

1.

2.

3.What about molecules? Or atoms?

DOZEN = 12 things

BUSHEL of corn = 21.772 kg

1 GROSS = 144 things

1 MOLE = ???

The Mole It represents a

counted number of things.

IN Chemistry the term MOLE represents the number of particles in a substance.

In Chemistry is NOT this furry little animal or the spot on your face…

Just how many is a mole? One mole represents 6.02 x 1023 of things (units,

molecules, compounds, formula units). This is called Avogadro’s number.

One mole of a substance contains 6.02 x 1023 particles.

1 mole Ag = 6.02x1023 atoms of Ag

1 mole H2O = 6.02x1023

molecules of H2O

602 000 000 000 000 000 000 000

Just how big is a mole?

An Avogadro's number of standard soft drink cans would cover the surface of the earth to a depth of over 200 miles

If you had Avogadro's number of un-popped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.

If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.

Sample Problems

How many molecules are in 3.00 moles of N2?

How many moles of Na are in 1.10 x 1023 atoms?

Practice moles to particles

Determine the number of atoms in 2.50 mol Zn.

Given 3.25 mol AgNO3, determine the number of formula units.

Calculate the number of molecules in 11.5 mol H2O.

Practice Particles to Moles

How many moles contain each of the following?5.75 x 1024 atoms Al3.75 x 1024 molecules CO2

3.58 x 1023 formula units ZnCl22.50 x 1020 atoms Fe

Mass & the Mole

Molar Mass Molar mass: is the mass, in grams, of

one mole of a substance Atomic masses (from periodic table)

represent molar mass. Units: g/mol 1 mole of Carbon has 6.02 x 1023 atoms of C

and they have a mass of 12.01 grams. The molar mass of carbon = 12.01 g

Molar Mass Practice

What is the mass of 1.00 mole of Oxygen? Of Nitrogen?

Find the molar mass for: SO3

Na2SO4

Tutorial Site

1 mole O = 16.0 grams

1 mole N = 14.0 grams

SO3= 80 g/mole

1 Mole = 142.043g

Practice Problems

Determine the molar mass of each of the following ionic compounds: NaOHCaCl2KC2H3O2

HCNCCl4H2O

Grams-Mole Conversions

How many moles are in 56.8 g of carbon?

How many grams are in 0.56 moles of Mg?

Practice Gram to moles

How many moles are in each of the following samples?55.2 g Li0.230 g Pb11.5 g Hg45.6 g Si0.120 g Ti

Mass to Particle Conversion Gold is one of a group of metals called the coinage

metals (copper, silver and gold). How many atoms of gold (Au) are in a pure gold nugget having a mass of 25.0 g?

Known: Unknown:

Mass = 25.0 g Au

Molar mass Au = 196.97 g/mol Au

Number of atoms = ? Atoms Au

Practice Problems Mass to Particles

How many atoms are in each of the following samples?55.2 g Li0.230 g Pb11.5 g Hg45.6 g Si0.120 kg Ti

Particle to Mass Conversion A party balloon contains 5.50 x 1022 atoms of helium

(He) gas. What is the mass in grams of the helium?

Known: Unknown:

Number of atoms = 5.50 x 1022 atoms He

Molar mass He = 4.00 g/mol Mass = ?

Practice Problems: particles to mass What is the mass in grams of each of the

following?6.02 x 1024 atoms Bi1.00 x 1024 atoms Mn3.40 x 1022 atoms He1.50 x 1015 atoms N1.50 x 1015 atoms U