Question

Which of the following has the highest kinetic energy?
A.Chalk
B.Hydrogen
C.Juice
D.Alcohol

Answer 1

First to solve this question, we need to know what kinetic energy is. Kinetic energy of any substance is the energy that an object has due to its motion of particles.
We know that among 3 states of matter, solid, liquid and gases, the particles have maximum movement in case of gases.

Complete step by step answer:

Now, when we come to know that the kinetic energy is the energy of Particles, due to the motion of particles, we should now start thinking of the 3 states of matter.
In solid substances, the particles are tightly packed, so the movement of particles is minimized or least among all 3 states of matter. While for liquids, the movement of particles is more than solids due to its loose packing, and thus the kinetic energy is more in case of liquids as compared to solids. While in case of gases, the particles are most free to move as they are loosely packed and thus gases possess maximum kinetic energy.
In the options, chalk is solid, hydrogen is gas while Juice and alcohol are liquids.
Hence the correct option is (B) Hydrogen, as this is gas among all 4 options and gas has maximum kinetic energy.

Additional information: For the same given substance, if we want to compare kinetic energy, then compare its temperature. The one with higher temperature will have greater kinetic energy than the one at lower temperature. Example: Cold water at 273 K has less kinetic energy as compared to hot water at 373K.

Note:
Kinetic energy is related to movement and freedom of molecules. We can compare the kinetic energy based on a few factors, the first factor is important, that is states of matter- solid, liquid and gas. For solid it is least and for gases it is most.
The second factor is temperature dependency, for the same state of matter. If more temperature then high kinetic energy.
Then the most fundamental principle is that the intermolecular distance and intermolecular force of attraction. If intermolecular distance is more, then the kinetic energy is high