Which isotope is appropriate for dating rocks that are billions of years old? oxygen-16

carbon-12

uranium-238

carbon-14

uranium-238

Explanation:

Uranium-238.

Uranium - 238' s half lif time is 4.5 billion years. This isotope decays until the stable isotope  Lead - 206.

It has been used to date the oldest rocks of the earth with a resulting age of approximately 4.0 billion years old.

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.

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explanation: