A pan containing hot water is left on the counter and becomes cool mainly due to A. water molecules moving apart.
B. cold air penetrating the hot water.
C. heat from the water moving into the cooler air.
D. hot water reacting with the metal pan.

C. heat from the water moving through the cooler air  

I think it's C because when something cools down, it has to reach a point of thermal equilibrium with the matter (in this case air) around it. So heat transfer happens through convection from the heat in the pan to the cooler surrounding air. The heated air becomes less dense and rises, while cooler air, sinks to the surface of the water, gets heated, and rises. This convection cycle keeps happening until the water in the pan is around the same temperature with the air around it.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

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