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.​

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.