Chemical Reactions

A change in the color of a solution is a sign that

• a chemical change is taking place.

• a physical change has just occurred.

• oxygen is present.

• organicd chemicals are present.

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

What kind of reaction occurs when potassium is placed in water?

• a single displacement reaction

• a double displacement reaction

• a decomposition reactions

• electrolysis

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

• polyethylene

• carbon dioxide

• sodium chloride

• copper (II) chloride

When methane reacts with abundant amounts of oxygen , the products are

• carbon dioxide and water

• carbon monoxide and water

• soot and water

• simple sugar and oxygen