Question

20.) the ph scale is used to measure how acidic or basic a substance is. the ph of a certain chemical is given by ph = - logh+, where h+ is the concentration of hydrogen ions in moles per liter.
a.) what is the ph of a solution for which h+ is 0.6? round to the nearest tenth.
b.) determine the hydrogen concentration of vinegar with ph = 1.2. round to four decimal places.

Explanation:

Step1: Substitute value into pH formula for part a

Given $pH = -\log[H^{+}]$, substitute $[H^{+}]=0.6$. So $pH = -\log(0.6)$.

Step2: Calculate the pH value for part a

Using a calculator, $-\log(0.6)\approx0.2218$. Rounding to the nearest tenth, $pH\approx0.2$.

Step3: Rearrange formula for part b

Starting with $pH = -\log[H^{+}]$, we can rewrite it as $\log[H^{+}]= - pH$. Then, by the definition of logarithms, $[H^{+}]=10^{-pH}$.

Step4: Substitute pH value into the rearranged formula for part b

Given $pH = 1.2$, then $[H^{+}]=10^{- 1.2}$.

Step5: Calculate the hydrogen - ion concentration for part b

Using a calculator, $10^{-1.2}\approx0.0631$.

Answer:

20a.) $0.2$
20b.) $0.0631$