Page 1 - 2-Lesson Notes-Common Causes of Physical and Chemical Changes
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SAI INTERNATIONAL SCHOOL
Class - VI
Subject - Chemistry
Topic – Changes Around Us
Sub-Topic – Common Causes of Physical and Chemical Change
Lesson Notes
COMMON CAUSES OF PHYSICAL AND CHEMICAL CHANGES:
➢ It is important to understand what factors affect the physical and chemical changes
of matter.
➢ Physical changes are about energy and states of matter. They can be seen and
measured.
➢ Physical changes are caused by forces like motion, temperature, and pressure.
➢ Chemical changes happen on a much smaller level, where, most of these changes
take place between the molecules and are unseen.
➢ Chemical changes bring about change in the chemical composition, forming a new
substance.
➢ We will study four common causes that make Physical and Chemical changes
happen, such as, Mixing, Chemical Reaction, Heating & Cooling, and the Application
of Force.
1) Mixing of two or more substances:
➢ Physical changes take place when two or more substances are mixed, where,
they do not react with each other.
➢ E.g., when salt is added to water, it forms a salt solution. The salt can again
be recovered from the solution by evaporating water and no new substances
are formed.
➢ Mixing of two or more substances can also bring about chemical changes.
➢ Here, two substances get reacted with each other to form new substances
with entirely different properties.
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