How many grams of KOH are needed to make 0.500 L of a 0.10 M solution

2.8 g KOH

Explanation:

We can find the amount of moles we need by multiplying 0.500 L and the molarity given, 0.10 M (molarity is moles of solute divided by liters of solution). The liters cancel out, leaving us with moles; we can then take the moles and convert it to grams of KOH by using the molar mass of KOH.

0.500 L x 0.10 mol/1 L x 56.106 g /1 mol = 2.8 g KOH (two significant figures)