Question

You measure the pH of your backyard soil and find it is 7. You measure the pH of your friend's backyard soil and find it is 4. How much greater is the concentration of the hydrogen ions in your friend's backyard than in your backyard?

Answer 1

Answer:

1000 times.

Explanation:

Hello,

In this case, since the pH is defined by:

$pH=-log([H^+])$

If we want to compute the concentration of hydrogen we must write:

$[H^+]=10^{-pH}$

Thus, for both the backyard soils we compute:

$[H^+]_{pH=7}=10^{-7}=1x10^{-7}M$

$[H^+]_{pH=4}=10^{-4}=1x10^{-4}M$

It means that:

$\frac{[H^+]_{pH=4}}{[H^+]_{pH=7}} =\frac{1x10^{-4}M}{1x10^{-7}M}\\ \\\frac{[H^+]_{pH=4}}{[H^+]_{pH=7}}=1000$

It means that the concentration of hydrogen at a pH of 4 is 1000 times greater than the concentration of hydrogen at a pH of 7.

Regards.