Match the following. match the items in the left column to the items in the right column. 1. the starting materials completely lose their properties to form new substances chemical change 2. a change from one state of matter to another phase change 3. a change in shape, size, or physical characteristics but remaining same substance law of constant composition 4. a pure compound consists of exactly the same elements in the exact same ratios by mass physical change 5. the smallest unit of a compound molecule