Question

The diagram shows molecules in a fluid. Explain the sequence of events that happens when this fluid cools down. Be sure to focus on what happens to the molecules and to the fluid in general. Five events should be included in your answer.

Answer 1

Answer:

When the fluid cools, the kinetic energy of the molecules decreases. This causes the molecules to slow down and move closer together. Since the molecules are closer together, the density of the fluid increases and the fluid sinks.

Explanation:

I just had the same one and that is the sample

Answer 2

The kinetic energy possessed by molecules decreases as the liquid cools down.

Explanation:

• As the liquid begins to cool, there is a reduction in the temperature of the fluid and a temperature gradient is created from the surface to the bottom.

• As the temperature reduces, the surface area occupied also reduces  molecules do not have enough space. Thus, the speed of movement of the molecules will also go on reducing with time.

• Since there is a reduction in speed with time the kinetic energy possessed by the molecules also reduces as KE = $\frac{1}{2}$ mv² where m is mass of molecules and v is velocity of the molecules.

• The density of the fluid increases as the temperature decreases as $p=\frac{M}{V}$where ρ is the density of the liquid, M is mass of the liquid and          V is volume of liquid . We know that as temperature decreases, volume   decreases and thus density increases as density is inversely proportional to volume.

• Thus as a fluid cools down, the movement of molecules becomes slower, subsequently causing surface area and volume to decrease. Therfore, on cooling a liquid becomes compact.