Select all the correct answers. properties of substances can be classified as physical or chemical properties. which statements describe chemical properties? a magnet is attracted to a piece of metal. a wire sags when weight is attached to it. silver tarnishes and becomes black when exposed to oxygen. water heated over a flame begins to bubble and evaporate. diesel fuel burns when it is heated.

              Silver tarnishes and becomes black when exposed to oxygen:

              Diesel fuel burns when it is heated:

Explanation:

                    Chemical Changes are those changes in which the chemistry at molecular level is changed as the starting material is converted in to a new and different final material. This change takes place with the breaking of old bonds and forming of new bonds respectively.

Silver tarnishes and becomes black when exposed to oxygen:

This is a chemical change as Silver a white and lustrous starting material is being converted into a tarnish black final material. However, Silver doesn't readily react with oxygen at normal conditions. It readily react with Sulfur containing compounds in air and produces black compound as Ag₂S.

Diesel fuel burns when it is heated:

Diesel is a mixture of hydrocarbons ranging approximately from C₁₀H₂₀ to C₁₅H₂₈. When these hydrocarbons are burnt they produces a new materials i.e. CO₂ and H₂O.

                             C₁₀H₂₀  +  15 O₂    →     10 CO₂  + 10 H₂O

Hence, it is also a chemical reaction.

Silver tarnishes and becomes black when exposed to oxygen:

              Diesel fuel burns when it is heated:

the dissolution of polymer can be thermodynamically described in 2 steps.