How many grams of solid potassium chloride is needed to prepare 250 mL to 0.235M solution

Question

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Answer 1

The molar mass of potassium chloride (KCl) is 74.55 g/mole

0.235 M KCl means 0.235 moles KCl in 1 liter of solution. 

Since the problem asks for only 250 ml of solution (not 1 liter), we adjust for that.  Recall 250 ml = 0.250 liters.

Thus...

0.235 moles/L x 0.25 L = 0.05875 moles KCl needed to make 250 ml

Now, to convert that to grams needed ...

0.05875 moles KCl x 74.55 g/mole = 4.38 grams KCl needed (to 3 significant figures)