Chemical Reaction #1

A release of energy is a sign that

• a chemical reaction is taking place

• a physical change just happened

• oxygen is present

• organic chemicals are present

Chemical energy is energy that is

• added to a reaction in the form of heat

• stored in the form of chemical bonds

• caused by the movement of electricity

• released only when oxygen is burned

Fragments of molecules that have at least one unpaired electron available for bonding are called

• ions

• orbits

• protons

• free radicals

In a redox reaction, the substance that accepts electrons is said to be

• reduced

• oxidized

• electrified

• clarified

Which of these is NOT a sign of a chemical reaction?

• a gas is given off

• the material dissolves

• heat is released

• a color change happens

The substance that is formed in a chemical reaction is called the

• polymer

• reactant

• radical

• product

Which of the following stores chemical energy?

• the temperature of a substance

• the density of a substance

• the bonds of a molecule

• the nucleus of an atom

Which of the following occurs in an endothermic reaction but not in an exothermic reaction?

• chemical bonds are broken

• energy is absorbed

• energy is released

• atoms are rearranged

A type of reaction that produces an increase in temperature is

• endothermic

• exothermic

• covalent

• nonpolar

A reaction in which the products contain more chemical energy than the reactants is

• exothermic

• electrical

• endothermic

• exergonic