We know that air is a mixture and not a compound because A. it can be heated to a higher temperature. B. it can be compressed to a smaller volume. C. it is colorless. D. its composition can vary.
2015 U.S. NATIONAL CHEMISTRY OLYMPIAD LOCAL SECTION EXAM Prepared by the American Chemical Society Chemistry Olympiad Examinations Task Force OLYMPIAD EXAMINATIONS TASK FORCE Seth N. Brown, Chair, University of Notre Dame, Notre Dame, IN James Ayers, Mesa State College, Grand Junction, CO Mark DeCamp, University of Michigan, Dearborn, MI (retired) Xu Duan, Holton-Arms School, Bethesda, MD Valerie Ferguson, Moore HS, Moore, OK Julie Furstenau, Thomas B. Doherty HS, Colorado Springs, CO Kim