IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: XaM!! on May 31, 2010, 04:39:14 pm

Title: bio prac doubt
Post by: XaM!! on May 31, 2010, 04:39:14 pm
Hey i have a question:
see there is a solution of 1 molar concentration..
how will we make a 10 cm3 of 0.2 molar concentratn?
Title: Re: bio prac doubt
Post by: Chingoo on May 31, 2010, 04:49:55 pm
Formula:
C1V1=C2V2
Meaning: (Required concentration)(Required Volume)=(Given Concentration)(Unknown volume to be diluted)
(0.2)(10)=(1.0)(V2)
V2= 2 cm^3.

There is actually less of a formula approach and more of a mathematical one. If you have math in your AS/A Level too, follow this. Otherwise, just remember the formula in it's real meaning.

0.2 moles of solute ----> 10 cm3 of solution
1.0 mole of solute ----> x cm3 of solution

(1.0)(x) = (0.2)(10)  {this is an inversely proportional relationship}
x = 2 cm3.
Title: Re: bio prac doubt
Post by: killzone on May 31, 2010, 05:14:45 pm
Formula:
C1V1=C2V2
Meaning: (Required concentration)(Required Volume)=(Given Concentration)(Unknown volume to be diluted)
(0.2)(10)=(1.0)(V2)
V2= 2 cm^3.

There is actually less of a formula approach and more of a mathematical one. If you have math in your AS/A Level too, follow this. Otherwise, just remember the formula in it's real meaning.

0.2 moles of solute ----> 10 cm3 of solution
1.0 mole of solute ----> x cm3 of solution

(1.0)(x) = (0.2)(10)  {this is an inversely proportional relationship}
x = 2 cm3.


so when u say v2 is 2cm^3 ...what volume is that ? volume of water or volume of solution being diluted nd the rest (8) is water ? plz explain?
Title: Re: bio prac doubt
Post by: XaM!! on May 31, 2010, 05:20:37 pm
Ya r v suppose to add 8cm3 water thn?
Title: Re: bio prac doubt
Post by: killzone on May 31, 2010, 05:22:51 pm
Ya r v suppose to add 8cm3 water thn?

Yea ..i asking the same thing >>? what does the 2 represent?
Title: Re: bio prac doubt
Post by: Chingoo on May 31, 2010, 05:30:18 pm
2 is the volume of a the sugar solution you will require. To make 10 cm3 you will add 8 cm3 water.
Title: Re: bio prac doubt
Post by: XaM!! on May 31, 2010, 05:51:42 pm
Hey chingoo Thanks a lot. b.d.w any news abt prac?