7th Class Science Physical and Chemical Changes Question Bank Physical and Chemical Changes

  • question_answer
    DIRECTIONS: Read the passage given below and answer the questions that follow. Passage - 1 A change in which two or more substances (reactants) combine to produce one or more new substances (products) that has/have different chemical properties than the reactants is called chemical change. In a chemical change new products are formed. The characteristics of a chemical change are following: 1. Heat, light or any other radiation (ultraviolet) may be given off or absorbed. 2. Sound may be produced. 3. A change in smell may take place or a new smell may be given off. 4. A colour change may take place. 5. A gas may be formed. Change in which only physical properties of any substances get changed and no new substance is formed is called a physical change. Such as shape, size, colour and state, is known as physical change. A physical change is mostly reversible and during physical change no new substances are formed. Which of the following statements is not correct?

    A) In a chemical change, colour of the object may change.

    B) In a chemical change, heat will always be released.

    C) A chemical change always involves physical change.

    D) Rusting of iron becomes faster when humidity is high.

    Correct Answer: B

    Solution :

    In a chemical change, heat will always be released.


You need to login to perform this action.
You will be redirected in 3 sec spinner