plz answer me.......6 std
Answers
Answer:
ans1) A change which can happen backward, that is, can be reversed is called a reversible change. If you keep water in the freezer for some time, it transforms into ice. But as soon as you take it out of the freezer, it turns into water again. This is a reversible change. Similarly, if you boil water, it evaporates and becomes water vapor. When you cool this vapor down, it turns back to water
A change which cannot happen backward, that is, it cannot be reversed is called an irreversible change. When you burn a piece of paper, it turns to ash. It cannot become paper again. Your height cannot decrease. These are irreversible changes. They cannot be reversed at all.
ans2) The difference between a physical reaction and a chemical reaction is composition. In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition.
ans3) Liquid
Liquids have the following characteristics:
no definite shape (takes the shape of its container)
has definite volume
particles are free to move over each other, but are still attracted to each other.
Example water, juce, mercury, etc.
Gas
Gases have the following characteristics:
no definite shape (takes the shape of its container)
no definite volume
particles move in random motion with little or no attraction to each other
highly compressible
Example oxygen, hydrogen, helium, etc.
Solid
Solids are defined by the following characteristics:
definite shape (rigid)
definite volume
particles vibrate around fixed axes.
Example is wooden chair, Tv, ice, iron rod, etc.
Explanation:
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Answer:
For the first question answer is ☝️☝️
Explanation:
For the second question the answer is .
When a substance undergoes a chemical change, its molecular composition is changedentirely. Thus, chemical changes involve the formation of new substances. Physical change is a temporary change. ... Some examples of physical change are freezing of water, melting of wax, boiling of water, etc..
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