Okay so I really don't get the concept of it. For example:
What is the molality of KNO3 (formula mass=101.1) that contains 202.2 grams of solute dissolved in 500 grams of water? Apparently the answer is 4 but I do not know how get it. The work I have is:
500g=1kg/1000g
=
500kg/1000
=
.5kg
then since m=mol/kg
m=2/.5kg
=
4m
So my question is why do you put the 500g on the other side of the equation when you start the problem off. Also where do you get the (1kg/1000g) from? Don't see how they relate to the question. And last question (sorry!) how do you figure out that "2" is the number of moles in that problem.
Thank you so much!
10 points will be given to the best answer
What is the molality of KNO3 (formula mass=101.1) that contains 202.2 grams of solute dissolved in 500 grams of water? Apparently the answer is 4 but I do not know how get it. The work I have is:
500g=1kg/1000g
=
500kg/1000
=
.5kg
then since m=mol/kg
m=2/.5kg
=
4m
So my question is why do you put the 500g on the other side of the equation when you start the problem off. Also where do you get the (1kg/1000g) from? Don't see how they relate to the question. And last question (sorry!) how do you figure out that "2" is the number of moles in that problem.
Thank you so much!
10 points will be given to the best answer
-
202.2gKNO3/500gH2O x 1molKNO3/101.1gKNO3 x 1000gH2O/1kgH2O = 4.000
Molality is the number of moles solute per 1 kg solvent. Molarity is the number of moles solute per liter of solution.
Molality is the number of moles solute per 1 kg solvent. Molarity is the number of moles solute per liter of solution.