Which of the following provides the best evidence that a chemical change is taking place? A. metal object becomes shorter when it is cooled. B. Steam rises from the surface of a liquid. C A liquid forms as a solid object melts. D. A flame burns on the surface of a solid.​

How does a scientist the government? a. the scientist tells people in society what to do. b. the scientist determines the policies that the government spends money on. c. the scientist provides unbiased information to the government. d. the scientist makes laws based on his or her research results.

11. phosphorus-32 is radioactive and has a half life of 14 days. how much of a 124 mg sample of phosphorus-32 is present after 56 days? a) 7.75 mg b) 15.5 mg c) 31.0 mg d) 62.0 mg

Areaction is first order with respect to reactant x and second order with respect to reactant y. which statement describes the rate law for this reaction?