Question

Which event is endothermic? the burning of a match the change of water vapor to a liquid the combustion of propane gas the melting of ice?

Answer 1

The melting of ice is an event which is endothermic. Endothermic is the process when heat is transfer from the environment to the object. It happens when the onject absorbs the heat just like melting of ice. The ice is in solid form due to the compaction of positively charged atoms in it but when heat carrying electrons made contact to it, it melted.

Answer 2

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.,

D is the correct answer.