what is the number of moles of solute in 250 ml of a 0.4 M solution

Question

molarity mass for chemistry question 

Answer 1

Hi Ryan,

To find the number of moles of solute in a volume of a solution, we need to multiply volume by concentration. BUT we also need to check that the units are the same. Molarity (M) is moles per liter, so we need to convert 250mL to L.

250mL=0.250L

 

Now we can multiply the concentration by volume.

0.4M*0.250L

 

This gives us the number of moles of solute.

Answer 2

The underlying formula you want to use to solve this one is

Molarity(M) = Moles / Volume(L)

For this scenario that means taking

Moles = Molarity x Volume

Moles = 0.4M x 0.250L

Moles = 0.1 mol

meaning that the number of moles of solute in 250 mL of a 0.4M solution is 0.1 mol