Comparing Molality & Molarity: Which is More Concentrated?

[Garvit Goel]

hello,
i had been comparing the molarity and molality of a solution.
i know molarity is moles of solute per L of solution, and molality is moles of solute per kg of solvents.
but what i m interested to know is- which of the two is more concentrated- 1molal solution or 1 molar solution.
my chemistry teacher said molarity is more concentrated. but i think it depends on the density if solvent if they are ideal solution.
I would really appreciate any assistance regarding this issue.

 

[Borek]

It is not only a function of a solution density, but also substance molar mass. It it probably possibleto find pairs substance/solvent such that for one molarity is higher, for other molality is higher. Which means there is no one answer to the problem.

 

[SpectraCat]

hello,
i had been comparing the molarity and molality of a solution.
i know molarity is moles of solute per L of solution, and molality is moles of solute per kg of solvents.
but what i m interested to know is- which of the two is more concentrated- 1molal solution or 1 molar solution.
my chemistry teacher said molarity is more concentrated. but i think it depends on the density if solvent if they are ideal solution.
I would really appreciate any assistance regarding this issue.

What do you mean by more concentrated? Do you mean, "if you convert a concentration of (1 mol solute)/(1 kg solvent) into molarity, is it higher or lower than 1 M?"

If that is what you are asking, then there is no way to answer the question. This is because different solute/solvent combinations result in solutions with different densities .. stated more specifically, we say that different solutes have different partial molar volumes. [EDIT: To clarify, this means that if you add a certain volume of solute to a certain volume of solvent, the volume of the resulting solution is NOT simply the sum of the two starting volumes.] To make it even more complicated, partial molar volumes depend on how much solute is added.