Question

Given that the molar mass of NaOH is 40.00 g/mol, what mass of NaOH is needed to make 2.500 L of a 2.000 M NaOH solution?

Answer 1

0.1250 g
5.000 g
32.00 g
200.0 g

Answer 2

Molarity = Moles/Liters

Moles = Grams/Molecular Mass

Video on how to calculate molecular mass
http://www.youtube.com/watch?v=F9NkYSKJifs

1. Figure out moles in the solution
2. Find molecular mass of NaOH plug that into other formula with the moles to find grams

Answer 3

how do you know how many moles are in a liter?

Answer 4

It is given. In this problem, the molarity is 2.000 M.

Answer 5

That means there are 2 moles of NaOH in 1 liter of solution.