Molality/Molarity - The difference
Molality - number of moles of solute dissolved in one
solvent. Molality is different from molarity because molality
about concentration in kilograms of solvent and molarity is
concentration in dm3 (liters) of solvent. Molality is
represented by a small 'm', whereas molarity is represented by
upper case 'M'. A 1 Molar
solution (1M) contains 1 mole of solute dissolved in a solution
totaling 1 liter
Molarity: How to prepare 1dm3 of a 2M KCl solution using chemistry
software CHEMIX School
Step 1 . Calculate the
weight of 2mol KCl (insert 2mKCl
in the Formula edit field (image below))
Step 2 To make a 2M
aqueous solution of KCl, dissolve 149.102 grams of KCl in some
distilled deionized water. Then add more water to the flask until it
totals 1 liter.
Molality and Solvents
Water as a solvent: Since water has a specific gravity of 1 (one dm3 = 1kg) , a molal concentration of 1m can be made by adding water to a volumetric flask up to the one liter line and then add the solute.
Other solvents are usually lighter than water and must therefore be weighed before adding the solute.
To make a one molal aqueous solution of potassium chloride,
out one kilogram of water and add one mole of KCl (74.55g/mole) to it.
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