Chemical Reactions

What describes a precipitate?

• A gas that escapes during a chemical reaction.

• A solid that forms in a liquid chemical reaction.

• A liquid that evaporates during a reaction.

• A color change that indicates a reaction has occurred.

Which is NOT an indication of a chemical change?

• color change

• temperature change

• shape change

• gas production

In a chemical reaction, no new atoms are created, and no atoms are _________________?

• Transformed

• Created

• Destroyed

• Eliminated

The production of carbon dioxide gas when baking soda and vinegar reacted indicated a _____________.

• Physical change

• Chemical change

• State change

• Phase change

Water evaporating is

• a chemical change

• a physical change

• a biological change

• a nuclear change

The Law of Conservation of Mass states

• that energy can be created or destroyed.

• that matter cannot be created or destroyed.

• that mass can change forms but is always conserved.

• that matter can be transformed into energy.

In a chemical reaction, what happens to the atoms of the reactants?

• The atoms of the reactants remain unchanged throughout the reaction.

• The atoms of the reactants break, rearrange, and then bond to form the products.

• The atoms of the reactants are destroyed and do not form products.

• The atoms of the reactants combine with other elements to create new reactants.

The starting substances that cause a chemical reaction are called

• products

• catalysts

• reactants

• intermediates

One of the signs of a chemical reaction taking place is:

• Bubbles are produced

• The temperature remains constant

• The color of the substance stays the same

• No gas is released

An example of a chemical reaction is

• a camp fire

• a melting ice cube

• boiling water

• dissolving sugar in water