Another solution question?

Question

How would you make 90 ml. of a 1.20 M aqueous solution of sodium oxalate (Na2C204) from a 2.00 M solution of sodium oxalate?

Please explain...

Answer 1

90mL = 0.09L
a solution of 90mL of 1.2M contains = 0.09*1.2 =0.108 mole

a 2.0M contains 2M in a Liter to have 0.108 mole you need
0.108/2 =0.054ml = 54mL

So you take 54 mL of solution 2.00M and add 90-54 =36mL of water