Learn about molar mass

1. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
Unit II: Countless and Active Particles of Matter
Module IV: What is in a Mole?
MOLAR MASS AND
PARTICLES OF THE
SUBSTANCES

2. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
Learning Objectives:
•Calculate for the molar mass of common
substances
•Give the number of particles in one
mole of the substance

3. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
What is a mole?
 MOLE is a collection of
particles equal to 6.02 x 1023
(atoms, ions, or molecules) of
a substance.

4. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
6.02 X 1023 particles/mole
• is also known as the
AVOGADRO’S NUMBER

5. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
How big is Avogadro’s number?
•602,000,000,000,000,000,000,000

6. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
WHAT DO YOU CALL THE MASS (IN
GRAMS) OF A MOLE OF A SUBSTANCE?
• MOLAR MASS is the
mass in grams of a mole
of a substance (g/mole)

7. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
THE MOLAR MASS OF AN ELEMENT IS
EQUAL TO ATOMIC MASS
ATOMIC MASS is the mass of one atom
of the element (in amu.)
 is the mass of one mole of any
element.

8. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
Example
• Gold (Au)
atomic mass = 197 amu
atomic mass = molar mass
Thus: molar mass = 197 g/mole

9. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
THE MOLAR MASS OF A COMPOUND IS
EQUAL TO THE FORMULA MASS
FORMULA MASS is the sum
of the masses of the atoms
present.
 the mass of one mole of any
compound.

10. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
Example
• Formula mass = (No. of atom of A x atomic mass
of A) + (No. of atom B x atomic mass of B) + …..
• Water (H2O)
• Formula mass = (2H x 1 amu) + (1 O x 16 amu) =
18 amu
• Formula mass = Molar mass
Thus, Molar mass = 18 g/mole

11. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
Let’s summarize
QUANTITY UNIT
MOLAR MASS g/mole
ATOMIC MASS/
FORMULA
MASS
amu

12. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
Examine the sample substances in the table
below
Substances Atomic
mass/Formula
mass
(amu)
Molar Mass
(g/mole)
Type of
substances
No. of
Particles/mole
Gold (Au) 197 197 Element 6.02 x 1023
atoms
Potassium
Chloride (KCl)
74 74 Ionic
Compound
6.02 x 1023
ions
Water (H2O) 18 18 Covalent
Compound
6.02 x 1023
molecules

13. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
DRILL: Find the molar mass of
the following compounds.
• Chemical Name Chemical
Formula
Molar Mass
(g/mole)
Iron (II) Sulphate
(ferrous sulfate)
Fe SO4
Ethyl Alcohol C2H5OH
Ammonia NH3

14. Schools Division Office of Cavite City
Ciudad de Cavite: Edukasyong Dekalidad, Serbisyong Dekalibre
Answer the Drill on your notebook