Why should a melting point determination sample never be reused?

The meting point is the temperature at which the solid state of the substance changes to the liquid state at the atmospheric pressure.

On melting, the substance may be decomposed slightly and there is a change in the structure of the substance that is on melting it goes from crystalline to amorphous structure and will not melt at the same temperature as the crystalline structure. Hence, the fresh sample must always be used for determining the melting point of the sample.

you should just be yourself and not let any body tell you other wise.

explanation:

why?

because if they don't love you for your self then they don't deserve you.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.