Physical and chemical changes Flashcards
Define CHANGE
A change is a transformation of a substance from one form to another
what are the changes seen when an object transforms
a change can be seen in :-
- Shape
-size
-Color
-state
-taste
State the different types of changes
- Natural and man-made
-desirable and undesirable
-reversible and irreversible
-Slow and fast - Periodic and non-periodic
- Physical & chemical
-exothermic and endothermic
Define physical change
A change in which the chemical composition of a substance remains the same and no new substance is formed.
Results of Physical Change
Change in
-state of matter
- Shape
-size
Examples of physical change
cutting of fruits, crushing of cans & bending a pipe
State the characteristics of physical changes
Processes classified as physical changes-
Evaporation
Boiling
Condensation
Freezing
Melting
Sublimation
Define and explain the process of Evaporation briefly
Process by which a substance changes from the liquid to its gaseous state is Evaporation. Since, there is no change in the physical composition thus, the process is a physical change that is slow, reversible, desirable and natural. Evaporation is affected by factors such as : Temperature , humidity, surface area and wind speed.
define and briefly explain boiling
The process by which a substance changes from the liquid to the gaseous state on heating is called boiling. The temperature at which a liquid is heated to become a gaseous substance is known as boiling point. Boiling of water is a physical change as its desirable, fast, man-made and reversible.
Define and explain Condensation briefly
Condensation is the process of cooling down a substance from its gaseous state to the liquid state is condensation. Its a physical change that is desirable reversible and natural.
Define and explain Freezing briefly
Freezing is defined as the process by which a liquid substance converts into its solid state on cooling or reduction of heat. Its a physical change as it can be reversible, fast, and can be natural as well as man-made.
Define Melting as well as its properties
Melting is defined as the process by which a solid mass gets converted into its liquid state on application of heat is melting. It is a physical process that is undesirable, reversible and fast.
Define sublimation
Sublimation is the process by which a substance is converted from the solid state to the gaseous state directly, without passing through the intermediate liquid state. It is a reversible, slow and natural process.
Give examples of substances that undergo sublimation
Naphthalene balls, Camphor, Iodine crystals, Ammonium chloride.
