Question

When a covalent or an ionic bond is formed a chemical change has occurred. Which of these is not associated with a chemical change?

A) The atoms of the substance produced have been rearranged.
B) The substances produced are identical to the substances that reacted except that they're isomers.
C) The total mass of the reacting substances is the same as the total mass of the substance produced by the reaction.
D) The chemical properties of the substances produced by the reaction are different from those of the reacting substances.

Answer 1

The answer is B). The total mass and the atom numbers of reacts and products are the same in the reaction. But that does not mean the production are identical to the reactants.

Answer 2

Answer: B) The substances produced are identical to the substances that reacted except that they're isomers.

Explanation: Chemical change is a change in which atoms of the reactants are rearranged ,thus leading to formation of new products.

The new substances formed are different compounds from the original reactants and thus they have different properties.

`2Na(s)+Cl_2(g)\rightarrow 2NaCl(s)`

This is an example of chemical reaction in which the bond between chlorine molecule is broken and a new bond between sodium and chlorine gets formed.

`NaCl` formed is an ionic compound whereas chlorine is a covalent compound and sodium is a metal.