Question

Physical changes (2 points)

are only caused through burning a material

cannot be detected by the naked eye

do not change the identity of the substance

change the identity of a substance

Answer 1

Physical changes do not change the identity of the substance. Heat causes chemical reactions. You cannot see chemical changes with the naked eye. The identity of a substance changes like when you burn paper, from paper it turns into ash and produces smoke, which are products from the chemical reactions.