Chapter 23, Problem 50A

Your inventor friend proposes a design for cookware that will allow boiling to take place at a temperature of less than $100°C$ so that food can be cooked with the consumption of less energy. Comment on this idea.

To determine

To Comment:On the idea that food can be cooked by boiling at a temperature less than $100°\text{C}$ for less consumption of energy.

Answer to Problem 50A

Boiling at a temperature less than $100°\text{C}$ can happen but food cannot be cooked as the temperature is very low.

Explanation of Solution

Introduction:The boiling point is the temperature at which a substance changes its state from liquid to gas at that particular pressure. The boiling point of water at atmospheric pressure is $100°\text{C}$ .

As the pressure decreases, the molecules of the substance move far from each other and it requires less energy to expand to the gaseous state. So, the temperature required to change the state decreases, and the boiling point of water decreases with the decrease in pressure on it.

But cooking of food does not depend on the boiling point. Rather, it depends on the heat given to the substance.

So,a decrease in the boiling point reduces the heat given to the substance, and hence, the food is not cooked at a lower temperature.

Conclusion:

Water can be boiled at a temperature less than $100°\text{C}$ but food cannot be cooked as the temperature is very low.