4. what two sets of units can be used to describe density? why are they interchangeable? a. b. c.

The density of a material is its unique property. Although the density can be expressed in different scale the density of the same material remains same. The reasons for the inter-changeability of the density are-

a. The density of a material is its unique property.

b. The density usually expressed in terms of CGS or SI unit. In CGS unit it is g/mL and in SI unit it is Kg/L.

c. In both the case if we multiply 1000 to gm it becomes kilogram (Kg) and 1000 unit of mL is liter (L). Thus the value remains same.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.