Chemistry help please...anyone?

Question

how do i calculate the molarity of CaCl2 in the following solution?

200 mL of 0.40 M CaCl2 diluted to 400 mL with water.?

please i really need help with this...

Answer 1

ok

x/0.2=0.4

so x=0.08mole

molarity=0.08/0.6

            =0.13M

Answer 2

failed chemistry TWICE! (T_T)

Answer 3

You've doubled the volume of the solution, so you have cut the concentration in half. The new concentration is 0.20M

In a more complicated problem you might want to use this relationship:

M1V1 = M2V2

where M is the molarity before and after dilution, and V are the volumes.

M2 = M1V1 / V2 = 0.40M x 200 mL / 400 mL = 0.20 M

Answer 4

You've doubled the volume of the solution, so you have cut the concentration in half.  The new concentration is 0.20M

In a more complicated problem you might want to use this relationship:

M1V1 = M2V2

where M is the molarity before and after dilution, and V are the volumes.

M2 = M1V1 / V2 = 0.40M x 200 mL / 400 mL = 0.20 M

====== Follow up =======

I see.  Apocalyp... thought you ADDED 400 mL to get a total volume of 600 mL, but you said that you diluted it TO 400 mL.