Chemical quantities

Chapter 10.1

Ways to measure matter

• Length/width/height• Volume• Density• Surface Area• Etc.

THE MOLE•THE SI UNIT FOR MEASURING THE AMOUNT OF A SUBSTANCE IS A MOLE.

Determining the amount of atoms in a

mole• NaCl has 2 atoms• MgO has 2 atoms• PF3 has 4 atoms

• 1 phosphorus • 3 fluorines

• C6H12O6 has 24 atoms in it• 6 carbons• 12 hydrogens• 6 oxygens

Representative Particles

• Atomic oxygen• O• 16.00 grams in one mole

• Oxygen Gas• O2

• 32 grams in one mole (2 atoms x 16)

Representative particles

• Sodium Ion• Na+• 22.99 g

• Sodium Chloride• NaCl• 22.99 g (Na) + 35.45 g (Cl)

Atomic mass• How many grams in 1 mole of

that element• OR• How many grams in 6.022 x

1023 atoms of that element

Atomic masses of elements

•Are based on the mass of the carbon isotope Carbon-12

Sulfur Trioxide• 1 x S = 1 x 32.1 = 32.1 amu• 3 x O = 3 x 16 = 48 amu• 48 amu + 32.1 amu = 80.1 amu• The atomic mass of a SO3 atom is 80

amu.

On your own:• H2O

• NH3

• PF3

• NaCl• C6H12O6

Molar Mass• The molar mass of a

compound is the mass of 6.02 x 1023 molecules of that compound.

• EX: The molar mass of H2O is 18.02 grams.

True or False?•Molar masses can be calculated directly from atomic masses expressed in grams.

•TRUE!