Which is a substance made up of only one kind of atom?
A. compound
B. solution
C. element
D. mixture

c

Explanation:

element only contain one atom

Any substance that has more than one atom is known as compound

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.