Classify each of these as an element, compound, or mixture: 3a. copper 3b. water 3c. nitrogen (see link attached to this post) 3d. sulfur 3e. air 3f. sucrose (table sugar) 3g. gasoline

Copper = Element

Water = Compound

Nitrogen = Element

Sulfur = Element

Air = Mixture

Sucrose = Mixture

Gasoline = Mixture

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.

explanation:

0.07 g/cm³

1.37 g/cm³