Question 8.SP.7: Calculating [H3O^+] from pH Determine the [H3O^+] for soluti......
Calculating [H_{3}O^{+}] from pH
Determine the [H_{3}O^{+}] for solutions having each of the following pH values:
a. pH=3.0
b. pH=8.2
a. For pH values that are whole numbers, the [H_{3}O^{+}] can be written 1\times 10^{-pH}.
\begin{matrix} &pH\\&\searrow \\ [H_{3}O^{+}]=1\times &10^{-3} M \end{matrix}b. For pH values that are not whole numbers, the [H_{3}O^{+}] is calculated as follows:
Step 1 Enter the pH value and press the change sign key.
8.2 \boxed{+/-} \overset{Calculator Display}{-8.2}
Step 2 Convert -pH to concentration. Press the 2nd function key and then the 10^{x} key. Or press the inverse key and then the log key.
\boxed{2^{nd}} \boxed{10^{x}} or \boxed{inv} \boxed{log} 6.3095^{-09} or 6.3095 E-09
Step 3 Adjust the significant figures in the coefficient. Because the pH value of 8.2 has one digit on the right of the decimal point, the [H_{3}O^{+}] is written with one significant figure.
[H_{3}O^{+}]=6 \times 10^{-9} M