Wednesday, April 20, 2011

Chemistry: Molality and Molarity

The concentration of solutions. If you need this, you know how it works.
--
(grams of solute) = (molality)(molar mass)(Kg solvent)
(grams of solute) = (molarity)(molar mass)(L solvent)
 --

-- Molality --
:Menu("Unknown:","M",1,"Mol.Mass",2,"Kg Solvent",3,"Grams",4)
:Lbl 4
:Input "M: ",M
:Input "Molar Mass: ", G
:Input "Kg Solvent: ",K
:(MGK)→A
:Disp "Grams:",A 
:Goto 99
:Lbl 3
:Prompt G,M
:Input "Mol.Mass",N
:(G)/(MN)→K
:Disp "Kg:",K
:Goto 99
:Lbl 2
:Prompt G,M,K
:(G)/(MK)→N
:Disp "Molar Mass:", N
:Goto 99
:Lbl 1
:Prompt G,K
:Input "Mol.Mass",N
:(G)/(NK)→M
:Disp "M",M
:Goto 99
:Lbl 99

-- Molarity --
:Menu("Unknown:","M",1,"Mol.Mass",2,"L Solvent",3,"Grams",4)
:Lbl 4
:Input "M: ",M
:Input "Molar Mass: ", G
:Input "L Solvent: ",L
:(MGL)→A
:Disp "Grams:",A 
:Goto 99
:Lbl 3
:Prompt G,M
:Input "Mol.Mass",N
:(G)/(MN)→L
:Disp "L:",L
:Goto 99
:Lbl 2
:Prompt G,M,L
:(G)/(ML)→N
:Disp "Molar Mass:", N
:Goto 99
:Lbl 1
:Prompt G,L
:Input "Mol.Mass",N
:(G)/(NL)→M
:Disp "M",M
:Goto 99
:Lbl 99

2 comments:

  1. Replies
    1. The best way would be to use the program. Or you can follow the calculator on that site. Molality is a mol/mass ratio of solute to solvent, so as long as you have the right units, you can do it any way you'd like. I would say that mols/mass would be simpler, but in the real world you most likely know your substance and you can measure its mass, so that it was I split it like so.

      Anyways, the best way is the way with which you are most comfortable

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