4
A C T
F
atom is smallest particle of an
element that has neutrons,
protons and electrons 5
U F F
B L
particle is a unit that includes
two or more atoms of one or
more elements 6
A C T
F
atom is the basic unit of
matter
7
Word Difficulty
Mole - The quantity of a substance that has
a weight, measured in grams, that is
numerically equal to the molecular weight
of that substance. Expressed as 6.02 ×
1023 particles (Avogadro’s number); mol is
used in equations; mole is used in writing.
Atomic Mass - The mass in atomic
mass units (amu) of one mole of a
substance.
Word Difficulty
Molar Mass - The sum of all the
atomic masses in a molecule or
compound; the mass in grams of one
mole of a substance.
Gram-mole - The mass of one
mole, or 6.02 × 10 particles,
23
expressed in grams.
WHO AM I?
A V O G A D R O
I am a 8 letter word. I am huge number and I am in charge of this unit’s discussion
1. A negative ion
2. The outer most electron
3. Element with an atomic number 8
4. Examples are helium, hydrogen and oxygen
5. First group in the periodic table
6. Sublevel with 5 orbitals
7. Second letter in the element symbol krypton
8. Rule that states that atom must have 8 valence electrons
10
Avogadro’s Number
1 Pair of socks
= 2 pieces of socks Do you know that it is impossible
to count the particles in a single
atom per molecule? To resolve this
problem , chemist used a quantity
= 2 pieces of shoes called mole The number 6.022 x
1 pair of shoes
1023 is called the Avogadro’s
number in honor of the Italian
scientist, Amedeo Avogadro (1776-
1856) who first suggested that it
1 dozen of donuts
= 12 pieces of donuts might be possible to count atoms .
This is indeed a very large number
that reflects the fact that atoms are
= 30 pieces of eggs very small.
1 tray of egg
1 ream of paper = 500 pieces of paper
11
Avogadro’s Number
A mole is the amount of a substance that has
the same number of particles (molecules,
formula units or atoms) as there are atoms in
12 grams of Carbon C-12. The number of
particles in 1 mole of any substance is given
by the value of :
or 602,000,000,000,000,000,000,000
6.02 x 1023
Avogadro’s Number
,here are some examples.
Hydrogen (H) = 1 g = 1mol
Calcium (Ca) = 40 g = 1 mol
Oxygen gas (O2) = 32 g= 1 mol
Water (H2O) = 18g = 1 mol
H= 2 x 1 g = 2g
O= 1 x 16g = 16g
18g/mol
Avogadro’s Number
Try this!
1. Silicon (Si) 28 g = 1 mol
2. Indium (In) 115 g = 1mol
3. Rubidium ( Rb) 85 g = 1mol
4. Sulfur (S) 27 g = 1 mol
5. Sodium Chloride ( NaCl) 58 g = 1 mol
Avogadro’s Number
The diagram bellow shows the Conversion process
from mass To mole, or mole to number of particles
and vice versa. Please observe the mathematical
Operation used in conversion.
divide by multiply by
Number
Mass Molar mass
Mol Avogadro’s number of
particles
multiply by divide by
desired unit
________________
desired unit = given unit x
given unit
Avogadro’s Number
REMEMBER! APPLICATION OF CONVERSION
• The Avogadro’s
Number and its
concept becomes
useful if and only if you mole
Mole = grams x
_______________
know how to use your
periodic
Grams
Table of elements
correctly. grams
________
Grams = mole x
• Use amu (atomic
mole
mass unit) or g/mol
(gram per mol) as unit
for mass of all
elements and
compound.
• Always use the right
formula for every
Avogadro’s Number
Sample problem 1.1.
(Mole to Mass)
1. What is the mass of 5.00 mol of Carbon (C)?
Identify the right formula .
St ___________
g
ep Mass = mol x
Mol of Carbon
1
St • Find the molar mass of the element ( C)
ep • C = 12 g
2
Substitute the given mole and the mass of the
element, then solve.
St 12 g
________
Mass = 5.00 mol C x 1 mol of C
ep
3 Mass = 60.00 g C
Avogadro’s Number
Let’s make it a little bit harder. Let’s use compound element.
Sample problem 1.2. (Mole to Mass)
1. What is the mass of 5.00 mol of Calcuimcarbonate (CaCl)?
To solve this problem , use the following steps:
Step 1: Identify the right formula .
MM of CaCl
Mass = mol ________________
mol of CaCl
Step 2: Calculate the molar mass of CaCl.
(number of atom x atomic mass)
Ca = 1 x 40 = 40 amu
Cl = 1 x 35 = 35 amu
75 g/mol
Step 3: Substitute all the given and calculated values in the formula.
Mass = 75 g of CaCl
___________
5.00 mol x
1Mol of CaCl
Mass = 375 g of CaCl
Avogadro’s Number
Sample problem 2.1. Mass to mole
How many moles are present in 25.6 g of C
St Identify the right formula.
1 mol
_________
ep Mol = mass x g
1
St • Find the molar mass of element (C)
ep • C = 12 g
2
Substitute the given mass and the molar
mass of the element, then solve.
St
Mole= 25.6 g x 1 mol of C
ep 12 g
Mol= 2.1 mol C
3
Avogadro’s Number
Again let’s make it a bit harder. Let’s use compound
element
Sample problem 2.2. (Mass to Mol)
1. How many moles are present in 25.6 g of CaCl ?
Follow the same steps as used in the first example.
Step 1: Identify the right formula .
mol of CaCl
_____________
Mol = mass
MM of CaCl
Step 1 Calculate the molar mass of CaCl.
(number of atom x atomic mass)
Ca = 1 x 40 = 40
Cl = 1 x 35 = 35
75 g
Step 3 Substitute all the given and calculated values in the formula.
____________
1 Mol of CaCl
Mol = 25.6 g x
75 g of CaCl
Mol = 0.3 mol of CaCl
Note! Don’t forget to cancel out all the unit so that the desired unit will remain
ACTIVITY
23
Avogadro’s Number
A # Station 1 Directions:
B $ Write your answer on the space provided by searching the codes with their
C %
corresponding letters. Pls. refer to the box at your left.
D ∆
E ∏
F ᴓ
G ᴥ
H Ω 1. Introduced the mole concept
I π # Σ # ∆ ∏ Ͽ # Ð Ͽ ᴥ # ∆ Ϟ Ͽ
J ۞
__ __ __ __ __ __ __ __ __ __ __ __ __ __
K ᴧ
L Ψ
M Σ 2. The mass of one mole of a substance .
N э # ˃ Ͽ Σ π % Σ # ˂ ˂
O Ͽ __ __ __ __ __ __ __ __ __ __
P Ͼ
Q Ͻ
3. The sum of all the atomic masses in a molecule or compound; the mass in
R Ϟ
S ˂ grams of one mole of a substance.
T ˃
U ˄ Σ Ͽ Ψ # Ϟ % Σ # ˂ ˂
V Ð __ __ __ __ __ __ __ __ __ __
W ö
X *
Y Ξ
Z ↑
24
Avogadro’s Number
Station 2
How many moles of carbon atoms
are contained
in 4g of Carbon ( C)?
25
Avogadro’s Number
It’s time to see if you have
understood the lesson we
Station 3 have just finished.
M
Answer the following questions:
O
1. How many mole are there in 12 g of Carbon? ______
2.. What is the mole in H2O?________ L
3. What is the famous number named after Amadeo Avogadro?
E
_____________
27
Y
Avogadro’s Number
Directions: Using the periodic table. What is the
atomic mass of the following
element.
Name of Element Symbol Atomic Mass Unit (amu) g/mol
1 Fluorine F
2 Carbon C
3 Oxygen O
28
Avogadro’s Number
Station 5
Directions:
What is the molar mass of the following compound?
Name of Compound Formula Name Formula Mas
1 Oxygen gas O₂ O = 2 x _____ = _____
Total
2 Carbon dioxide CO₂ C = 1 x _____=_____
O = 2 x_____ =_____
Total
3 Calciumcarbonate CaCO₃ Ca = 1 x _____ = _____
C = 1 x _____ =______
O = 3 x _____ =_____
Total
29
Avogadro’s Number
Evaluation
1. The mass in atomic mass units (amu) of one mole of a substance.
a. Molar mass c. mole
b. atomic Mass d. 1g/mol
2. The sum of all the atomic masses in a molecule or compound; the mass in
grams of one mole of a substance
a. Molar Mass c. mole
b. Atomic mass d. 1g/mol
3. How many moles are there in water ( 1 Mole)
a. Molar Mass c 1 mole
b. Atomic Mass d avogadros number
4. Chemist who propose Avogadro’s Number.
a. Amadeo Avogadro c. Robert Boyles
b. Charles Darwin d. Jacques Charls
5. What is atomic mass unit of hydrogen?
a. Molar Mass c. particles
b. Atomic Mass d. 1 g/mol)
42
Avogadro’s Number
Evaluation
1. The mass in atomic mass units (amu) of one mole of a substance.
a. Molar mass c. mole
b. atomic Mass d. 1g/mol
2. The sum of all the atomic masses in a molecule or compound; the mass in
grams of one mole of a substance
a. Molar Mass c. mole
b. Atomic mass d. 1g/mol
3. How many moles are there in water ( 1 Mole)
a. Molar Mass c 1 mole
b. Atomic Mass d avogadros number
4. Chemist who propose Avogadro’s Number.
a. Amadeo Avogadro c. Robert Boyles
b. Charles Darwin d. Jacques Charls
5. What is atomic mass unit of hydrogen?
a. Molar Mass c. particles
b. Atomic Mass d. 1 g/mol)
43
44
