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 physical change 2. a change from one state of matter to another molecule 3. a change in shape, size, or physical characteristics but remaining same substance phase change 4. a pure compound consists of exactly the same elements in the exact same ratios by mass chemical change 5. The smallest unit of a compound Law of Constant Composition