In a heating and cooling curve, I understand that the flat part means that the bonds are either forming or breaking, depending on if the input of energy is increasing or decreasing, but what is happening to the bonds in the slanted parts?

Question

Thanks!

Answer 1

They're back together in their new state.

ICE (Slant)<-- Crystalloid formed molecules; they are vibrating slightly but packed together so tightly they do not move. As
TRANSITION FROM ICE TO LIQUID <-- since heat is being applied molecules are moving about more and slowly the ice is melting to liquid because of this; while this straight part of the graph an equilibrium is occurring; there is a equal amount of water as there is ice.
LIQUID (SLANT)<-- Molecules are moving around in this state. Molecules are forming and breaking but there is not enough heat to change the state.
TRANSITION FROM LIQUID TO GAS <--- both liquid and gas are present in a equilibrium state, gas molecules (which more faster) are forming and escaping the liquid phase
GAS (SLANT) <--molecules moving as freely and as fast as possible

what i'm trying to tell you is that the slants are to show you that from x area to y area this is at a constant state for those energy/heat levels. It then transitions, preforming a phase change. after the change, from x area to y area it is once again at a constant state for those energy/heat levels.

Answer 2

Ok, makes sense. Thanks!

Answer 3

I think what you have to understand is that on the flat portion, the temperature is constant because the phase change is occurring and the temperature cannot go up (if melting) or down(if crystallizing) until all of the molecules have melted or crystallized. At that exact point on the way up, added heat can go to increasing temperature of the liquid or on the way down heat can be extracted from the crystals that have formed.