What is the number of moles of solute in 650ml of a 0.40M solution?

Given the concentration as molarity, we can use the following formula to solve for the moles

moles = Molarity x Liters

Molarity = 0.40 M

liters = 650 mL = 0.650 L

moles = 0.40 x 0.650 = 0.26 moles

V=650 ml = 0.65 l

c=0.4 mol/l

n=vc

n=0.65 l * 0.4 mol/l = 0.26 mol