Answer:
D. The melting of ice
Explanation:
An endothermic reaction ABSORBS heat from its surroundings, it does NOT give heat off into its surroundings.
so...
When a match burns, it gives of heat. So A is incorrect.
When water goes from a vapor into a liquid, the water molecules loose kinetic energy, they do not gain it. And since temperature is the measure of the average kinetic energy in a substance, the water vapor looses heat. If the process was endothermic, it would be gaining heat. So B is incorrect.
When propane gas combusts, the explosion lets off heat into its surroundings, it does not absorb heat. So C is incorrect.
Here's what happens when something melts: the molecules inside the substance receive more and more kinetic energy, until the substance's molecules have enough kinetic energy to vibrate and wiggle past each other, breaking their structure. When ice melts it is receiving kinetic energy from its surroundings, and again, since temperature is the measure of the average kinetic energy in a substance, the process is absorbing heat. Q.E.D.,
<em>D</em> is the correct answer.
