Molality- the number of moles of solute per kilogram of ...



Molality- the number of moles of solute per kilogram of solvent. Its symbol is a script (M)

Mass percentage-percent by mass of the solute in solution. So it would be the total mass of solute divided by the total mass of solution

Mole fraction- used for two component solutions, when there are more than one solute in a solution. Moles of one of the solutes per total moles of all solute.

• Molality is the number of moles of solute per mass of solvent.

• The molality of a solution is calculated by taking the moles of solute and dividing by the kilograms of solvent.

[pic]

Example #1 - Suppose we had 1.00 mole of sucrose (it's about 342.3 grams) and proceeded to mix it into exactly 1.00 liter water. It would dissolve and make sugar water. We keep adding water, dissolving and stirring until all the solid was gone. We then made sure everything was well-mixed. What would be the molality of this solution?

The answer is 1.00 mol/kg

Example #2 - Suppose you had 2.00 moles of solute dissolved into 1.00 L of solvent. What's the molality?

The answer is 2.00 m

Example #3 - Suppose you had 58.44 grams of NaCl and you dissolved it in exactly 2.00 kg of pure water (the solvent). What would be the molality of the solution?

0.500 mol/kg or 0.500 molal

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download