Question

Use the formula pH = log (1/H*) to find the pH of the substance given its concentration
of hydrogen ions in a liter of acid rain that has a pH. Round your answer to the nearest
ten-thousandth.
10. pH = 3.6

Answer 1

We can use the subtraction property of logs to expand the right side of the equation:

log(1/H*) = log(1) - log(H*)

No matter what base we’re using, log(1) = 0, so this simplifies to -log(H*). We’re also given a pH value of 3.6, so we can substitute this value into the original equation along with -log(H*) to get

3.6 = -log(H*)

Multiplying by -1 on both sides:

-3.6 = log(H*)

And rewriting in exponential form:

H* = 10^(-3.6) = 0.0003 (rounded to the nearest ten thousandth)