2. Contents
• Introduction: Learning Objectives
• Definition of Mass
• What is Stoichiometry?
• Usage of Molar Mass
• Mole
• Equation Balancing
• Practice
4. Let's Think...
What is doing chemistry?
-explains everything that you can see
-how it looks
-the way it feels
-why it behaves the way it does
-helps us to understand the biggest things in the universe by helping us to
understand tiniest
-traffics in infinitesimal particles, and we are made of those things - they are building blocks of mass
We are MASSIVE!
5. So, what is
Mass?
-in daily life we need to understand how
much of something is there before we
can use it or predict the usage
Chemistry will tell you Atomic Structure of a
Sugar C-12, H –22, O-11
6. But how to understand
how much sugar do I
need in my "Şirin Çay?"
or how that molecule of
sugar will react in my
body?
I need to know the MASS of
sugar that I am dealing
with...
7. Stoichiometry is
a Science of...
• Measuring chemicals that GO
INTO and come OUT OF any given
reaction
• In Greek "MEASURING
ELEMENTS"
• Allows us to COUNT atoms and
molecules by WEIGHING THEM
8. What is Relative
Atomic Mass?
The average atomic mass of all the
naturally occurring Isotopes of a given
element
9. Atomic Mass
• We measure it in amu (atomic mass
units) - 1/12 of the mass of an atom
of 12C - since 1961
• C= 12,01 amu; O= 16 amu;
H= 1,008 amu
How many amu-s of these
molecules are going to make this
taste good?
10. In order to make calculations we need...
• To convert the atomic mass of this sugar into a standard amount of
substance – not WEIGHT, not VOLUME just purely amount of STUFF
That is what MOLE is for...
NOT THIS ONE! 😊
11. MOLES
• One of the most important unit in all chemistry – because it
allows us to express a chemical's atomic mass in terms of grams
There are 6,022 x 1023 atoms in 12 grams of 12C
6,022 x 1023- is known as Avogadro's Number
• he used basic principle of comparing amounts
of substance to weigh atoms and molecules
12. Cont...
• A dozen roses – 12 roses , mole of
roses - 6,022 x 1023 roses
• P.S. enough amount to cover the
whole world :)
• In Chemistry a mole of any element
contains 6,022 x 1023 atoms of that
element no matter what
• It let us translate numbers of atoms
into grams – we can weigh them
13. Cont...
• 1 mole of 12C = 6,022 x 1023 atoms (12 grams)
• 1 mole of 16O = 6,022 x 1023 atoms (16 grams)
One mole of any element equals its relative mass in grams:
Molar mass (M) in gram = Relative Atomic Mass (RAM) in amu
• 1 mol H = 1,008 g
• 1 mol Fe = 55,85 g
This is known as Molar Mass
