1. what mass of sodium hydroxide is required to make up 100 mL of 0.5000M solution

2.What volume of this solution must be diluted down to 100 mL if 0.100M solution of NaOH is required?

1 answer

1.
How many moles do you need? That's mols = M x L = ?
Then convert to grams. mols = g/molar mass. You know mols and molar mass, solve for grams.

2. Use the dilution formula.
mL1 x M1 = mL2 x M2
mL1 x 0.5 = 100 x 0.1
Solve f r mL1.