Physical Science 7.3

Multiple Choice

During a chemical reaction, an input of energy is always required to

• break chemical bonds in a molecule

• build chemical bonds as a molecule forms

• separate products from reactants

• change reactants to the liquid phase so they can react

Multiple Choice

In an exothermic reaction, the total chemical energy of the products added to the energy released by the reactions is

• less than the energy of the reactants

• equal to the chemical energy of the reactants

• greater than the chemical energy of the reactants

• not related to the chemical energy of the reactants

Multiple Choice

Combustion is always an exothermic reaction

• true

• false