Chemical Reactions

A substance that undergoes a change in a chemical reaction is

• a product

• a chemical

• a reactant

• an enzyme

What happens in a chemical reaction?

• atoms are destroyed

• atoms are created

• molecules are created

• atoms are rearranged

In an exothermic reaction, energy is transferred from

• the reactants to the surroundings

• the surroundings to the reactants

• one reactant to another

• the container to the chemicals

Chemical energy is energy that is

• added to a reaction in the form of heat.

• present within atoms and molecules.

• caused by the movement of electricity.

• released only when oxygen is present.

The energy source in photosynthesis is

• light energy

• chemical energy

• heat energy

• kinetic energy

A synthesis reaction is a reaction between at least two compounds in which

• one breaks down into at least two products

• a compound is decomposed by an electric current

• a compound burns in the presence of oxygen

• a new more complex compound is formed

The product of the synthesis reaction between sodium and chlorine gas is

• polyethylene

• carbon dioxide

• sodium chloride

• copper (II) chloride

When water is broken down by electrolysis, the products are

• water and carbon dioxide

• hydrogen and oxygen ions

• hydrogen gas and oxygen gas

• oxygen and methane

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

• reduced

• oxidized

• electrified

• clarified

A chemical equation is balanced by changing or adding

• chemical symbols

• subscripts

• coefficients

• reactants