1. Section 4: Moles of Compounds
Chapter 7: Chemical Composition

2. Learning Goals 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.

3. Chemical Formulas and the Mole
Chemical formulas indicate the numbers and types of atoms contained in one unit of the compound.

4. Chemical Formulas and the Mole
One mole of CCl2F2 contains one mole of C atoms, two moles of Cl atoms, and two moles of F atoms.

5. Chemical Formulas and the Mole
Determine the number of moles of Cl- ions in 2.50 mol of ZnCl2.
How many moles of oxygen atoms are present in 5.50 mol of diphosphorus pentoxide.

6. Chemical Formulas and the Mole
Determine the number of moles of sulfate ions present in 3.00 mol of Iron (III) sulfate.
Calculate the number of moles of each element in 1.25 mol of C6H12O6.

7. The Molar Mass of Compounds
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.
The molar mass of a compound demonstrates the law of conservation of mass.

8. The Molar Mass of Compounds
Determine the molar mass of each compound:
NaOH
CaCl2
Potassium acetate

9. The Molar Mass of Compounds
Determine the molar mass of each compound:
C2H5OH
HCN
Carbon tetrachloride

10. Converting Moles to Mass
For elements, the conversion factor is the molar mass of the compound.
The procedure is the same for compounds, except that you must first calculate the molar mass of the compound.

11. Converting Moles to Mass
What is the mass of 3.25 mol of H2SO4?
What is the mass of 4.35 x 10-2 mol of zinc chloride?

12. Converting Mass to Moles
The conversion factor is the inverse of the molar mass of the compound.

13. Converting Mass to Moles
Determine the number of moles present in each compound:
22.6 g AgNO3
6.50 g ZnSO4
35.0 g hydrochloric acid

14. Converting Mass to Particles
First, convert mass to moles of compound with the inverse of molar mass.
Then, convert moles to particles with Avogadro’s number.

15. Converting Mass to Particles
A sample of ethanol (C2H5OH) has a mass of 45.6 g.
How many carbon atoms does this sample contain
How many hydrogen atoms are present?
How many oxygen atoms are present?

16. Converting Mass to Particles
A sample of sodium sulfite has a mass of 2.25 g
How many Na+ ions are present?
How many SO32- ions are present?