question_answer

While heating ice in a beaker with a thermometer suspended in it, a student recorded the following observations Time 0 1 2 3 4 5 6 7 8 10 15 20 25 30 35 (in min) Temp -3 -1 0 0 5 8 12 15 19 22 30 50 73 100 100 (in °C) Based on the above observations, answer the following questions (i) State the change (s) observed between 2 min to 3 min and name the process involved. (ii) Between 30 min to 35 min, the temperature remains constant. State the reason for this. Name the heat involved in the process and define it.

Answer:

                (i) Between 2 min to 3 min, ice is converted into the water and this process is called fusion.                                                                 (ii) Between 30 min to 35 min heat is used for converting water (liquid) to vapour (gas), so temperature during this period remains constant. It is due to the latent heat of vaporisation.                                                      Latent Heat of Vaporisation Amount of energy required to change 1 kg of water to its vapours at its boiling point is known as latent heat of vaporisation.