Calculate the grams or milliliters of solute needed to prepare the following solution
1. 150 mL of a 40.0% (m/v) LiNO3 solution
2. 450 mL of a 2.0% (m/v) KOH solution
3. 225 mL of a 15% (v/v) Isopropyl alcohol solution
1. Percent m/v means grams solute/100 mL OF SOLUTION.
For 150 mL you will need 40.0 x 150/100 = 60 g LiNO3.
So you want to place 60.0 g LiNO3 in a 150 mL volumetric flask, add some distilled water, swirl to dissolve the solid, then add enough distilled water to make to the mark of the volumetric flask. Stopper. Mix thoroughly. Label. Done.
#2 is done the same way.
#3 is v/v. For a 15% solution you want 15 g isopropyl alcohol in 100 mL OF SOLUTION. So 15 g isopropyl alcohol (that's rubbing alcohol) in 100 mL volumetric flask, add distilled water to the mark, shake, etc etc. You want 225 so scale that up from 15 g in 100 mL to ? g in 225 mL.
Post your work if you get stuck.
NOTE: There is a tendency among most students to think they can add 15 g solute to 85 mL (15 mL alcohol + 85 mL water = 100 mL solution) BUT THAT ISN'T SO. For example, if I mix 50 mL ethyl alcohol and 50 mL distilled water it makes 95 mL of solution (not 100 ml) so you must watch that wording.