Chemical Reactions

In a ___________change, a substance changes into a different substance.

• Physical
• Chemical

Which of these is NOT a sign that a chemical change has occurred? 

• A loss of transparency 
• An unexpected color change
• A temperature change
• The formation of a precipitate

The Law of Conservation of Mass states

• that matter exists in all states and reacts the same
• that matter can only be changed into new substances by introducing a catalyst
• that matter exists in the same state throughout any chemical change
• that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants

a copper penny turning greenish after a few years.

• Chemical Change
• Physical Change

Which of the following IS a physical change?

• Getting a haircut
• Rusty metal
• sour milk
• A compound

___________________ are the elements or compounds that leave (are formed in) a chemical

reaction.

• Polymers

• Bonds

• Reactants

• Products

The smell made from spraying perfume on yourself. 

• Chemical Change
• Physical Change

The smell your dog makes after eating to much people food.

• Chemical Change
• Physical Change

In a ___________change, a substance changes into a different substance.

• Physical
• Chemical

What indicates a chemical reaction occurred?

• Heat or Light is released
  heat or light is produced
• gas (bubbles) produced
• color change
• all of the above