26. Under what conditions heat can be given to a substance without raising its temperature ?
25. Why is heat energy needed to melt a solid ? What is this heat energy called ?
Answers
Answer:
25.Every state of matter has particles which posses some attraction with each other.
Solid particles has high attraction ,Liquid has less force of attraction and Gas has least force of attraction.
Inorder to change state from solid to liquid it is required to break down the force of attraction between particles.To break this attraction heat is need which is being used or absorb to break force of attraction between particles.
So in process of melting heat is required.And this heat is known as Latent Heat of Fusion or Latent heat of melting.
26.When the substance is at its boiling or melting point, heat can be given to it without raising it's temperature. This is so because the heat supplied is used in changing the phase of the substance (liquid to gas or solid to liquid) and there isn't a change in its temperature.
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