Transcript Defining the Atom

Chapter 10 Chemical Quantities
10.1 The Mole
Chemistry
Today we are learning to:1. Understand the relationship between moles, Avogadro’s
number and gram formula mass
2. Use gram formula mass to convert grams of a substance into
moles
3. Use gram formula mass to convert moles of a substance into
grams
17.1
The Mole
Exothermic and
Endothermic Processes
1 mole is defined a the number of atoms of carbon present in exactly 12g of
carbon-12.
This number of atoms is called Avogadro’s number and is equal to 6.022x1023
atoms.
It follows that:
1 mole of any element = 6.022x1023 atoms = atomic mass of element
1 mole of any compound = 6.022x1023 formula units/molecular formula = gram
formula mass of compound
The mole can be abbreviated to mol
17.1
Converting
Exothermic and
GramsEndothermic
to Moles Processes
To convert from grams to moles use the formula:
1 mol
moles = number of grams x -------------------------------Gram formula mass
Converting Moles to Grams
To convert from moles to grams use the formula:
Gram formula mass
grams = number of moles x -------------------------------1 mol
17.1
Converting
Exothermic and
MolesEndothermic
to Grams Processes
Sulfuric acid
Ex.1 how many grams are present in 40.5 mol of H2SO4?
1. Identify the knowns and unknowns
moles of H2SO4 = 40.5
mass of H2SO4 = ?
2. Calculate gram formula mass.
For H  2 x 1.0 amu = 2.0 amu
For S  1 x 32.1 amu = 32.1 amu
For O  4 x 16.0 amu = 64.0 amu
formula mass = 98.1 amu
3. Plug in the numbers and solve equation
Gram formula mass
Mass g = number of moles x ---------------------------1 mol
98.1 g
Mass g = 40.5 mol x ----------1 mol
Mass g = 3970 g
Try question 27-50 on page 50-51 of review book
END OF SHOW