What happens to the average kinetic energy of the molecules of a warm substance when the temperature of the substance is slightly decreased? (5 points) group of answer choices it increases. it decreases. it becomes zero. it remains unchanged.

decreases

Explanation:

the particles have less kinetic energy as the thermal heat is decreased

Option (b) is the correct answer.

Explanation:

Average kinetic energy is defined as half of mass of gas times the square of root mean square velocity.

Mathematically,    Average K.E =

Also,   Kinetic energy =

So, when there is increase in temperature then there will be increase in movement of the molecules. As a result, kinetic energy will also increase. Since, kinetic energy is proportional to temperature.

Therefore, with decrease in temperature there will be decrease in average kinetic energy of the molecules.

Thus, we can conclude that the average kinetic energy of the molecules of a warm substance also decreases when the temperature of the substance is slightly decreased.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.