Understanding Physical and Chemical Changes

What is the primary difference between a physical and a chemical change?

• Physical changes create new substances.

• Chemical changes are reversible.

• Chemical changes do not alter the substance.

• Physical changes do not create new substances.

Which of the following is an example of a physical change?

• Burning a match

• Folding paper into origami

• Mixing vinegar and baking soda

• Rusting of iron

What new substances are formed when a match is burned?

• Oxygen and hydrogen

• Carbon dioxide and water vapor

• Nitrogen and methane

• Sulfur dioxide and ammonia

Which of the following is NOT a clue that a chemical change has occurred?

• Change in shape

• Formation of bubbles

• Heat production

• A drastic color change

What causes the Statue of Liberty to change color over time?

• Reaction with oxygen

• Exposure to sunlight

• Physical abrasion

• Contact with water

What is produced when Alka-Seltzer tablets are placed in water?

• Oxygen gas

• Nitrogen gas

• Carbon dioxide gas

• Hydrogen gas

What is the role of reactants in a chemical reaction?

• They are the by-products.

• They are the final products.

• They are the catalysts.

• They are the substances that start the reaction.

In the experiment with beakers, what is being observed?

• The color of the liquid

• The temperature of the beaker

• The presence of a chemical reaction

• The weight of the beaker

What is a product in a chemical reaction?

• A substance that initiates the reaction

• A new substance formed as a result of the reaction

• A substance that is consumed during the reaction

• A catalyst that speeds up the reaction

Which of the following is an example of a chemical change?

• Burning wood

• Melting ice

• Boiling water

• Cutting paper