Chemistry paper 5

[diwash]

Hello evvery one
I am having problem while varying concentration keeping total volume constant....
Lets see an example...
we are provided with 2.0 mol/dm^3 Nacl...how can we prepare 5 solutions with different concentration of Nacl by dilution with water...
I know how to vary concentration when total volume need not to be constant
Can any one explain me how to do it ...(with calculation)

 

[soumayya]

For dilution problems, u need to use the formula M1V1 = M2V2,
where M1= initial conc, V1= volume of solution to be used, M2= conc. required n V2= volume required.
For example, if we want to prepare solns wiz conc 0.0 , 0.5 , 1.0 , 1.5 n 2.0 mol/dm^3.

Preparing 10 cm^3 of 0.5 mol/dm^3 NaCl..
M1V1 = M2V2
2.0 * V1 = 0.5 * 10
V1 = 2.5

Thus,to make 10 cm^3 of 0.5 mol/dm^3 soln of NaCl, we need 2.5 cm^3 of the 2.0 mol/dm^3 NaCl soln and 7.5 cm^3 of water(i.e to make it to 10 cm^3)

lyk zat u calculate for the other conc...

Hpe zat hlps...