Question

17 multiple choice 1 point which of the following is a physical change? you leave a bicycle out in the rain and it rusts burning hydrogen acid corrodes reacts with a lead (pb) pipe water freezing 18 multiple choice 1 point which of the following is a chemical change? boiling gatorade candle burning cutting a candle melting candle wax

Explanation:

1. For question 17: A physical change is a change in which the substance's chemical composition remains the same. Water freezing is a change of state from liquid to solid, but the water molecules remain the same chemically. Rusting of a bicycle is a chemical reaction with oxygen (oxidation), burning hydrogen is a combustion reaction, and acid - lead reaction is a chemical reaction.
2. For question 18: A chemical change results in the formation of new substances. Candle burning is a combustion reaction that produces carbon dioxide and water, changing the chemical composition of the wax. Boiling Gatorade is a physical change (change of state), cutting a candle is a physical change (change in shape), and melting candle wax is a physical change (change of state).

Answer:

1. Water freezing
2. Candle burning