Which is the best evidence that a chemical change has occurred? a. change of state b. release of energy c. temperature change d. formation of a new substance

The answer to your question is: letter D.

Explanation:

Chemical change is when one substance combines with another one to form a new one.

A. change of state  this is a physical change, there is not hte formation of a new compound.

B. release of energy this is not a evidence of a chemical change, this option is wrong.

C. temperature change this is not a characteristic of a chemical change, this is not the right answer.

D. formation of a new substance this is the correct answer is the main characteristic of a chemical change.

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.