Chapter U5.3, Problem 10E

Interpretation Introduction

Interpretation:

The reason due to which when a campfire burns out, the ashes eventually cool to the temperature of the surrounding air that needs to be explained.

Concept Introduction :

When two substances are in physical contact with each other but there is no exchange of heat energy, it is known as thermal equilibrium.

Answer to Problem 10E

The heat transfer from the burning ashes to the surrounding until it reaches thermal equilibrium, and then it cools down.

Explanation of Solution

It is known that the temperature is used to measure the coldness and hotness of a body. Two main concepts that impact the temperature are thermal equilibrium and thermal contact. Two substances are said to be in thermal contact if they affect the temperature of each other. Two substances are in thermal equilibrium when they are in thermal contact but there is no change in the temperature.

When campfire burns, H₂O &CO₂ are formed from hydrocarbon reactions. This is an exothermic reaction which releases energy to the surrounding. Thus, products at a higher temperature finally burn down all the hydrocarbons and the reaction stops.

Ashes will keep losing energy until it reaches in thermal equilibrium with the surroundings and therefore will cool down.