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This is the answer to chapter 14, problem number 61 from the zoomdahl chemistry textbook.
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This problem asks us to calculate the concentration of an aqueous hbr solution that has a ph of 4 .25.
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And the problem also says hbr is a strong acid.
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Okay.
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And so ph equals 4 .25.
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And the reason that we're being told that hbr is a strong acid.
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Acid is because strong acids are going to dissociate completely in water.
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So we have an aqueous hbr solution here.
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The ph is 4 .25.
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So our concentration of hbr is going to be equal to our concentration of hydrogen ions.
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And we can calculate the concentration of hydrogen ions because we know that ph is equal to the negative log of the concentration of hydrogen ions.
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Okay.
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And then, as i said, for a strong acid, the concentration of that acid, so h .a.
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Not, let's call it.
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So the initial concentration of the acid is going to be equal to the concentration of hydrogen ions.
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Okay, so all that we need to do now is solve the ph equation...