Question

what is the ph for a solution with $oh^- = 8.9 \times 10^{-9}$ m?
respond with the correct number of significant figures in scientific notation (use e notation and only 1 digit before decimal e.g. 2.5e5 for $2.5 \times 10^5$)
type your numeric answer and submit
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question 16
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what is the ph of a solution $oh^- = 8.9 \times 10^{-9}$ m when converting $oh^-$ to poh, then converting that value to ph.
respond with the correct number of significant figures in scientific notation (use e notation and only 1 digit before decimal e.g. 2.5e5 for $2.5 \times 10^5$)
type your numeric answer and submit

Explanation:

Step1: Calculate pOH from $[OH^-]$

$\text{pOH} = -\log_{10}[OH^-] = -\log_{10}(8.9 \times 10^{-9})$
$\text{pOH} = 8.0506$

Step2: Relate pOH to pH

At 25°C, $\text{pH} + \text{pOH} = 14.00$
$\text{pH} = 14.00 - 8.0506$

Step3: Round to sig figs, format to E notation

$\text{pH} = 5.9494 \approx 5.9$ (2 significant figures, formatted as $5.9\text{E}0$ per required style)

Answer:

$5.9\text{E}0$