Problem 18 - Entrance Test

A chemical change involves the formation of new substances with different chemical properties. Physical changes alter the form or appearance but not the chemical composition. - A) Melting of ice: Water changes from solid to liquid. It is still H₂O. (Physical change) - B) Dissolving sugar in water: Sugar molecules disperse in water but do not change chemically. (Physical change) - C) Burning of a candle: The wax (a hydrocarbon) reacts with oxygen from the air to produce carbon dioxide, water, light, and heat. New substances are formed. (Chemical change) - D) Boiling of water: Water changes from liquid to gas. It is still H₂O. (Physical change)