Question

The diagram below shows the temperature dropping from 80°C to 20°C.

Molecules that have longer arrows are moving faster. Which statement describes what is happening in this system?
A) Molecules vibrate more as temperature decreases.
B) Temperature is not related to the average kinetic energy of a system.
C) Kinetic energy decreases as temperature decreases.
D) There is no change in average kinetic energy between these two systems.

Answer 1

Answer: Option (C) is the correct answer.

Step-by-step explanation:

At high temperature, molecules will have more kinetic energy and therefore, they will rapidly move from one place to another.

Also, kinetic energy is directly proportional to temperature. That is, more is the temperature more will be kinetic energy of molecules of a substance.

Whereas less is the temperature less will be kinetic energy of molecules of a substance.

Therefore, when temperature changes from
`80^(o)C` to
`20^(o)C` then kinetic energy will decrease.

Hence, we can conclude that the statement kinetic energy decreases as temperature decreases is happening in this system.

Answer 2

Answer is: C) Kinetic energy decreases as temperature decreases.

The average kinetic energy of molecules depends on the temperature.

As temperature increases, molecules gain more energy from surrounding and move faster (as is shows at the diagram).

Kinetic energy (standard unit is the joule J) depends on speed of the molecule.