Chapter 9, Problem 7RAT

The density of water at $4\text{°C}$ will slightly increase when it is

(a) cooled.

(b) warmed.

(c) Both.

(d) Neither.

To determine

The correct option for the statement "The density of water at $4\text{°C}$ will slightly increase when it is".

Answer to Problem 7RAT

The correct option for the statement "The density of water at $4\text{°C}$ will slightly increase when it is" is option (c).

Explanation of Solution

The water freezes at $0\text{°C}$ and boils at $100\text{°C}$ . Ice is a solid form of water and contains a lot of space in the crystal lattice of ice. When the ice melts, the density of liquid water increases till $4\text{°C}$ due to the collapsing of crystal structure of ice.

When the warm water is cooled down, the motion of the water molecules gets slow and the density of the water increases. Due to cooling of the liquid till $4\text{°C}$ , the formation of ice clusters takes place, and molecules get apart from each other, so the density of water increases and this results in the maximum density of water at $4\text{°C}$ . So the density of water will slightly decrease when its temperature gets change.

Conclusion:

Therefore, the correct option for the statement "A bimetallic strip used in thermostats relies on the fact that different metals have different" is option (c).