Question

how many grams are there in 0.250 moles of NaOH?

Answer 1

we are asked to find the mass of 0.250 mol of NaOH
molar mass of NaOH - 40 g/mol
in other words 1 mol of NaOH has a mass of 40 g
therefore 0.250 mol of NaOH has a mass of - 40 g/mol x 0.250 mol = 10.0 g
mass of 0.250 mol of NaOH is 10.0 g