Definition of density in a really simple kid friendly way .

Density is a measurement that compares the amount of matter an object has to its volume. An object with much matter in a certain volume has high density. An object with little matter in the same amount of volume has a low density.

Density is found by dividing the mass of an object by its volume.

p=m/v

where ρ is the density, m is the mass, and V is the volume.

in the analysis of systems that involve fluid flow, we frequently encounter the combination of properties u and pv.

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.