batter and cake are different substances & baking a cake turns batter into a cake ->  baking a cake produces a different substance  burning a match will produce ashes & lighting a match causes that match to burn ->  lighting a match causes the match to produce ashes  lighting a match causes the match to produce ashes & match and ashes are different substances ->  lighting a match produces a different substance  baking a cake produces a different substance & lighting a match produces a different substance ->  baking a cake and lighting a match both produces different substances  baking a cake and lighting a match both produces different substances & chemical reactions cause different substances to form ->  lighting a match and baking a cake are both chemical reactions  lighting a match and baking a cake are both chemical reactions & chemical reactions cause chemical change -> lighting a match and baking a cake are both chemical changes