During photosynthesis, carbon dioxide and water combine according to this general equation. Why is photosynthesis a chemical reaction? A. change of state
B. release of energy
C. temperature change
D. formation of a different substance that wasn't there before

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.