Learning Goals
0 Convert between grams and moles.
0 Convert between grams and number
of atoms or molecules.
0 Convert between moles of a
compound and moles of a
constituent element.
0 Convert between grams of a
compound and grams of a
constituent element.
Chemical Formulas and the Mole
0 Chemical formulas indicate the
numbers and types of atoms
contained in one unit of the
compound.
Chemical Formulas and the Mole
0 One mole of CCl2F2 contains one
mole of C atoms, two moles of Cl
atoms, and two moles of F atoms.
Chemical Formulas and the Mole
0 Determine the number of moles of
Cl- ions in 2.50 mol of ZnCl2.
0 How many moles of oxygen atoms
are present in 5.50 mol of
diphosphorus pentoxide.
Chemical Formulas and the Mole
0 Determine the number of moles of
sulfate ions present in 3.00 mol of
Iron (III) sulfate.
0 Calculate the number of moles of
each element in 1.25 mol of
C6H12O6.
The Molar Mass of Compounds
0 The molar mass of a compound
equals the molar mass of each
element, multiplied by the moles of
that element in the chemical formula,
added together.
0 The molar mass of a compound
demonstrates the law of
conservation of mass.
The Molar Mass of Compounds
0 Determine the molar mass of each
compound:
0 NaOH
0 CaCl2
0 Potassium acetate
The Molar Mass of Compounds
0 Determine the molar mass of each
compound:
0 C2H5OH
0 HCN
0 Carbon tetrachloride
Converting Moles to Mass
0 For elements, the conversion
factor is the molar mass of the
compound.
0 The procedure is the same for
compounds, except that you must
first calculate the molar mass of
the compound.
Converting Moles to Mass
0 What is the mass of 3.25 mol of
H2SO4?
0 What is the mass of 4.35 x 10-2 mol
of zinc chloride?
Converting Mass to Moles
0 The conversion factor is the
inverse of the molar mass of the
compound.
Converting Mass to Moles
0 Determine the number of moles
present in each compound:
0 22.6 g AgNO3
0 6.50 g ZnSO4
0 35.0 g hydrochloric acid
Converting Mass to Particles
0 First, convert mass to moles of
compound with the inverse of
molar mass.
0 Then, convert moles to particles
with Avogadro’s number.
Converting Mass to Particles
0 A sample of ethanol (C2H5OH) has a
mass of 45.6 g.
0 How many carbon atoms does this
sample contain
0 How many hydrogen atoms are present?
0 How many oxygen atoms are present?
Converting Mass to Particles
0 A sample of sodium sulfite has a
mass of 2.25 g
0 How many Na+ ions are present?
0 How many SO32- ions are present?