Understanding Chemical Reactions

Which of the following is NOT an indicator of a chemical reaction?

• Permanent color change

• Fizzing or bubbles

• Change in odor

• Increase in mass

What is a common example of a chemical reaction that involves a change in temperature?

• Dissolving sugar in water

• Burning a candle

• Melting ice

• Mixing vinegar and baking soda

What role do electrons play in chemical reactions?

• They change the color of substances

• They are responsible for the release of gases

• They increase the mass of the reactants

• They recombine to form new substances

What happens when electricity is run through water?

• It changes color

• It becomes ice

• It separates into hydrogen and oxygen

• It turns into steam

When hydrogen and oxygen recombine, what is the result?

• Water and energy release

• A change in color

• A decrease in temperature

• A solid precipitate