Question

How would 250 ml of o.15 M KNO3 solution be prepared?(in form of equation)

Answer 1

You want how many moles? That's M x L = 0.15 x 0.250 = 0.0375
grams KNO3 = mols x molar mass = 0.0375 x 101 = 3.79 g
So the formula is M x L x molar mass = grams.