Chemistry
In a chemical change :
- a new substance is formed
- energy is either released or absorbed
- the change is irreversible
- all of the above
Phy & Chem Changes
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Answer
all of the above
Reason — A chemical change is a permanent and irreversible change in which new substances are formed whose chemical composition and physical and chemical properties are different from those of the original substance. During a chemical change, exchange of energy takes place, depending on the nature of the reaction.
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Related Questions
Which of the following is a slow change?
- Rusting of iron
- Burning of wood
- Burning of a cracker
- Switching on a fan
Which of the following is a physical change?
- Cooking of food
- Formation of curd
- A glass cut into pieces
- Boiling of eggs
Assertion (A): The changes which result in the formation of new substances with entirely different composition and properties are called chemical changes.
Reason (R): Chemical changes are permanent and irreversible.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false
- A is false but R is true.
Assertion (A): When a change in a substance can be reversed by changing the conditions, it is said to be a reversible and temporary change.
Reason (R): Burning a piece of paper is a reversible change.
- Both A and R are true and R is the correct explanation of A.
- Both A and R are true but R is not the correct explanation of A.
- A is true but R is false
- A is false but R is true.