Lactic acid, grams, molarity?

Question

Tell me how to do this please?

How many grams of lactic acid (C3H6O6) are in a 0.5 M solution of lactic acid? (12C1H16O)

That's exactly how it looks on my paper. And also:

How many grams of salt (NaCl) must be dissolved in water to make 2 liters of a 2M salt solution?

Answer 1

About the 1st question I must know the volume

moles = molarity x Volume ( in L)

if V = 1.0 L

moles = 0.5 x 1.0 = 0.5

Mass = 0.5 mol x 90 g/mol =45 g

Moles NaCl = 2 M x 2 L = 4

mass NaCl = 4 mol x 58.44 g/mol =233.8 g