PPT: Atoms and Molecules | Science Class 9 PDF Download

 Page 1


Atoms & Atoms &
Molecules Molecules
Page 2


Atoms & Atoms &
Molecules Molecules
Introduction to Introduction to Atoms and Molecules Atoms and Molecules
Atoms and molecules are the smallest
building blocks of matter.
They make up everything we see and touch
in the world around us.
Early ideas about atoms were based on
thoughts, not experiments.
Antoine Lavoisier and Joseph Proust
created laws of chemical combination, to
explain how atoms and molecules
combine.
Page 3


Atoms & Atoms &
Molecules Molecules
Introduction to Introduction to Atoms and Molecules Atoms and Molecules
Atoms and molecules are the smallest
building blocks of matter.
They make up everything we see and touch
in the world around us.
Early ideas about atoms were based on
thoughts, not experiments.
Antoine Lavoisier and Joseph Proust
created laws of chemical combination, to
explain how atoms and molecules
combine.
Laws of Laws of  Chemical Combination Chemical Combination
Given by Lavoisier and Joseph L. Proust as follows:
Law of Conservation of Mass 
Mass can neither be
created nor destroyed in
a chemical reaction
A + B ? C + D
Reactants ? Products
Mass of reactants = Mass of products
Example:
Page 4


Atoms & Atoms &
Molecules Molecules
Introduction to Introduction to Atoms and Molecules Atoms and Molecules
Atoms and molecules are the smallest
building blocks of matter.
They make up everything we see and touch
in the world around us.
Early ideas about atoms were based on
thoughts, not experiments.
Antoine Lavoisier and Joseph Proust
created laws of chemical combination, to
explain how atoms and molecules
combine.
Laws of Laws of  Chemical Combination Chemical Combination
Given by Lavoisier and Joseph L. Proust as follows:
Law of Conservation of Mass 
Mass can neither be
created nor destroyed in
a chemical reaction
A + B ? C + D
Reactants ? Products
Mass of reactants = Mass of products
Example:
Page 5


Atoms & Atoms &
Molecules Molecules
Introduction to Introduction to Atoms and Molecules Atoms and Molecules
Atoms and molecules are the smallest
building blocks of matter.
They make up everything we see and touch
in the world around us.
Early ideas about atoms were based on
thoughts, not experiments.
Antoine Lavoisier and Joseph Proust
created laws of chemical combination, to
explain how atoms and molecules
combine.
Laws of Laws of  Chemical Combination Chemical Combination
Given by Lavoisier and Joseph L. Proust as follows:
Law of Conservation of Mass 
Mass can neither be
created nor destroyed in
a chemical reaction
A + B ? C + D
Reactants ? Products
Mass of reactants = Mass of products
Example:
Laws of Laws of  Chemical Combination Chemical Combination
Given by Lavoisier and Joseph L. Proust as follows:
Law of Constant Proportions
In a chemical substance, the
elements are always present in
definite proportions by mass.
 In water, the ratio of the mass of
hydrogen to oxygen is always 1:8,
whatever the source of water,
river, well or rain.
Example: