Question icon
Grade 12Physical Chemistry

which is better for express concentration molarity or molality

Profile image of deepraj
11 Years agoGrade 12
Answers icon

7 Answers

Profile image of Aarti Gupta
11 Years ago
Molality is considered better for expressing the concentration as compared to molarity because the molarity changes with temperature because of expansion or contraction of the liquid with temperature.But molality does not changes with temperature because the mass of the solvent does not change with change in temperature.
Profile image of Avinash
11 Years ago
Molarity and molality are both measures of concentration of solutions. One is the ratio of moles to volume of the solution and the other isthe ratio of molesto the mass of the solution.
Molality is better than the molarity concentration in chemisrtry pratical calculation becauseConcentrations in molality (moles of solute per kilograms of solvent) are independent of temperature and pressure whereas concentrations in molarity (moles of solute per total volume of solution in liters) are not.
Profile image of Avinash
11 Years ago
Molality is independent of temperature
Profile image of Prajwal Kavad
11 Years ago
molality is better bcoz it doesnt change with temperature
Profile image of Aanya
7 Years ago
As we all know that molality is moles per mass of solvent where mass does not depend on temperature whereas molarity is moles per volume where volume is temperature dependent .
This is the only reason that molality is better than that of molarity.
Profile image of manish sharma
6 Years ago
The concentration %(w/w), molality and mole fraction require mass of substance. With change in temperature, mass remains same. So, these are temperature independent concentration. But for molarity and normality, we have to calculate volume which generally increases with increase in temperature, so concentration value decreases. So, it is better to express concentration in molality rather than molarity.
Profile image of Rishi Sharma
5 Years ago
Dear Student,
Please find below the solution to your problem.

Molarity and molality are both measures of concentration of solutions.
One is the ratio of moles to volume of the solution and the other isthe ratio of molesto the mass of the solution.
Molality is better than the molarity concentration in chemisrtry pratical calculation because concentrations in molality (moles of solute per kilograms of solvent) are independent of temperature and pressure whereas concentrations in molarity (moles of solute per total volume of solution in liters) are not.
Molality is independent of temperature

Thanks and Regards