Chapter 7: Chemical Composition
Date:____________
Section 4: Moles of Compounds - Notes
Objectives:
 Convert between grams and moles.
 Convert between grams and number of atoms or molecules.
 Convert between moles of a compound and moles of a constituent element.
 Convert between grams of a compound and grams of a constituent element.
Chemical Formulas and the Mole:
 Chemical formulas indicate the ________________________________ of atoms contained in
one unit of the compound.

One mole of _______________ contains _____ mole of C atoms, _____ moles of Cl atoms, and
_____ moles of F atoms.

Practice:
o Determine the number of moles of Cl- ions in 2.50 mol of zinc chloride.
o
How many moles of oxygen atoms are present in 5.50 mol of diphosphorus pentoxide?
o
Determine the number of moles of sulfate ions present in 3.00 mol of iron (III) sulfate.
o
Calculate the number of moles of each element in 1.25 mol of C6H12O6.
The Molar Mass of Compounds:
 The molar mass of a ____________________ equals the molar mass of each _______________,
multiplied by the moles of that element in the chemical formula, added together.

The molar mass of a compound demonstrates the law of _______________________________.

Practice: Determine the molar mass of each compound below:
o
NaOH
o
C2H5OH
o
CaCl2
o
HCN
o
Potassium acetate
o
Carbon tetrachloride
Converting Moles to Mass:
 For elements, the conversion factor is the ___________________________ of the compound.

The procedure is the same for compounds, except that you must first calculate the
_______________________________ of the compound.

Practice: Determine the mass of each of the following:
o 3.25 mol of H2SO4
o
4.35 x 10-2 mol of zinc chloride
Converting Mass to Moles:
 The conversion factor is the _________________ of the molar mass of the compound.

Practice: Determine the number of moles present in each compound:
o
22.6 g AgNO3
o
6.50 g ZnSO4
o
35.0 g of hydrochloric acid
Converting Mass to Particles:
 First, convert mass to moles of compound with the _______________________ of molar mass.

Then, convert moles to particles with ___________________________ number.

Practice:
o
o
A sample of ethanol (C2H5OH) has a mass of 45.6 g.
 How many carbon atoms does the sample contain?

How many hydrogen atoms are present?

How many oxygen atoms are present?
A sample of sodium sulfite has a mass of 2.25 g.
 How many Na+ ions are present?

How many SO32- ions are present?