1.
A solution of compound X of concentration 0.5 M is diluted 20 times. Calculate the number of mmoles of X present in 20 ml of the resulting solution.
My Method:
0.5M X 20 = 10 M ,therfore moles = 10 M x 0.02 L = 0.2 moles therefore = 2x10e-4 mmoles.
Is this correct?
2.
2 ml of a solution of X of concentration 0.30 mM was added to 6 ml of water. What is the number of mmoles of X in 0.50 ml of this solution.
My method: 0.05 ml x 0.30 = 0.15 therefore 0.15 x 6 = 0.9 therefore = 9x10e-4 mmoles
Is this correct?
3.
20 grams of X is dissolved in a total of 500 ml. 100 ml of this solution is diluted 20 times. How many mmoles are present in this solution (Mr of X is 80)?
My method : Moles of X = 20/80 = 0.25 in 500 , and i dont know where to go from here?!
Thank you for your time guys.