how many mls of glycerol (FW= 92.1; density=1.26g/ml) must be used to make 250ml of a 0.15 M solution

Answer 1

M = moles/L
You know M and L, solve for moles.

Then moles = grams/molar mass
You know moles and molar mass, solve for grams.

Using density, convert grams to mL.