A student heats a beaker containing ice and water. He measures the temperature of the beaker as a function of time and draws the following graph:
What does the curve ab represent?
What happens after 25mins?
What does the curve bc represent?
At what temperature and time does ice melt?
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The curve ab represents the phenomenon of melting (or fusion). The process in which a solid state of matter changes into its liquid state is called fusion/melting at its melting point.
After 25 mins, the water in the liquid state starts to increase in temperature due to the external heat provided, and liquid particles from the surface of the water start to gain heat energy.
The curve bc represents the change of water from its liquid state (water) to its gaseous state (water vapor) which is called evaporation and this eventually leads to the boiling of water. The temperature is gradually increasing after all the ice is converted to water.
Melting is a process in which matter changes from its solid state to its liquid state and according to the given graph, ice starts melting at 273K for a time span of 25mins.