Fig. 1 shows an ice rink worker spreading a thin layer of water over a cold rink surface. The water freezes to form a smooth solid layer. Later, a repair te...
Question 1 Report
Fig. 1 shows an ice rink worker spreading a thin layer of water over a cold rink surface. The water freezes to form a smooth solid layer. Later, a repair team uses a warm air blower to remove a small patch of ice without adding more water. The temperature of the rink is monitored throughout the repair.
(a) Name the change of state when the water layer forms ice. [1]
(b) State the melting temperature of pure water, in degrees C. [1]
(c) Explain why the particles in the ice cannot move from place to place. [2]
(d) Give three differences between particles in liquid water and particles in water vapour. [3]
(e) Explain why energy is needed to melt the ice even though the temperature stays at 0 degrees C during melting. [3]
Answer Details
(a) Water changing to ice is freezing, also called solidification. [1]
(b) The melting temperature of pure water is 0 °C. [1]
(c) In ice, particles are held in fixed positions by forces of attraction. They cannot move from place to place and only vibrate about their positions. [2]
(d) Three paired differences are: liquid particles are close together, whereas water-vapour particles are far apart; liquid particles move more slowly, whereas vapour particles move faster; attractions are stronger in liquid water, whereas they are very weak or negligible in water vapour. [3]
(e) Energy is absorbed during melting to overcome forces of attraction between particles. It is not used to increase particle kinetic energy, so the temperature stays at 0 °C while melting occurs. [3]
Download The App On Google Playstore
Everything you need to excel in your exams
