4) 10.2 grams; molarity is the moles/liter so you do
x/.4(it must be liters)=.3 which will give you the moles
moles =.12
you find the molar mass of NaNO3 which is= 85grams
.12moles x 85 grams = 10.2 grams
5)629.28 grams;
again you do moles/liter = molarity and we are given the molarity and liters to find the moles;
plug in .4=x/4.6
moles= 1.84
then you multiply the moles(1.84) by the molar mass(342)=
629.28g
6) moles/liter= molarity
your given molarity and mililiters (convert to liters by dividing by 1000) to find moles
.75=x/1.25
moles=.9375
moles x molar mass
.9375 x 74.08 = 69.45
Hope these could help!