When a solid is placed in a container and heat is applied, a phase change occurs. - True
Temperature remains constant while all of a solid is converted to a liquid. - True.
When heat is applied to a solid, the molecular motion decreases as the temperature increases - False.
The average kinetic energy of the system changes while all of a solid is converted to a liquid. - True.
The temperature increases while all of a liquid is converted to a gas. - False.
When a solid is converted to a liquid, heat is absorbed. - True.
<h3><u>Explanation:</u></h3>
During heating the solid, the solid absorbs heat from the source of heat, and then it increases the average kinetic energy of the solid which at last undergoes a phase change as the temperature of the solid reaches its melting point, and then melts into liquid.
During the phase change, the temperature of the whole body remains constant because during this time, the molecular state and the crystal state of the solid changes, which actually consumes the energy. So the kinetic energy of the molecules do not change, which in turn don't change the temperature.
During heating the molecular motion of the solid increases because the heat energy is absorbed by the solid, which is changed to kinetic energy in the molecule. So heating increases the kinetic energy of the molecules of solid.
The average kinetic energy of the system increases while the solid changes to liquid, because of the increase in freedom of the molecules.
During change of state the temperature of a body doesn't increase, the reason is discussed above.
During the change of state from solid to liquid, the kinetic energy of the molecules increase, which is obtained from the heat source. So heat is absorbed.
