question_answer

  (i) What is matter? Write two properties of solids and two properties of liquids. (ii) Give reasons for the following. (a) Ice at 0°C appears colder in the mouth than water at 0°C. (b) Doctors advise to put the strips of wet cloth on the forehead of a person having high temperature.

Answer:

                  (i) Matter is a substance which has mass and occupies space.                                                 (1) (b) In solids force of attraction between particles is strongest and intermolecular space is very less.                                                        (1) (b) In liquidsforce of attraction is relatively less and more intermolecular space is more in comparision to solids.                                     (1) (ii) (a) As ice absorbs the latent heat of fusion too from the mouth so, it feels colder than the water at the same temperature, i.e., 0°C.              (b) As the temperature of the patient's body is high, the water from the wet strips evaporates by absorbing the heat from the body. This lowers the body temperature of the patient. That's why doctors advised to put the strips of wet cloth on the forehead of a person suffering from high fever.