What mass of potassium hydroxide, $KOH$ , is required to make $250$ $cm^3$ of a $0.5$ $M$ solution?

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Answer 1 · 2016-05-22T10:33:28

$250$ $cm^3$ = $0.25$ $dm^3$ (= $0.25$ $L$ )

For a solution, $C=n/V$ (concentration = number of moles/volume). Rearranging, $n=CV=0.50xx0.25=0.125$ $mol$

We need $0.125$ $mol$ of KOH and the molar mass of KOH is $56.1$ $g$ $mol^-1$ , so $56.1xx0.125=7.0$ $g$ . We need $7.0$ $g$ of KOH.

What mass of potassium hydroxide, KOHKOH, is required to make 250250 cm^3cm^3 of a 0.50.5 MM solution?