Further information 3.2 Measures of concentration

A useful measure of concentration of component J of a mixture is its mole fraction, the amoimt of J molecules expressed as a fraction of the total amoimt of molecules in the mixture. In a mixture that consists of Ha A molecules, ng B molecules, and so on (where the nj are amounts in moles), the mole fraction of J (where J = A, B.) is 

In this figure, the mole fraction Xa of component A (in blue) of a binary mixture increases from (a) 0.167, to (b) 0.452, to (c) 0.833. 

The molar concentration, [J] or Cj, of a solute J in a solution (more formally, the amount of substance concentration ) is the chemical amount of J divided by the volume of the solution  

Molar concentration is typically reported in moles per cubic decimeter (and commonly as moles per liter, mol L ). The unit 1 mol dm is commonly denoted 1 m (and read molar ). Once we know the molar concentration of a solute, we can calculate the amount of that substance in a given volume, V, of solution by writing 

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Further information 3.2 Measures of concentration 130 Discussion questions Exercises Projects... 

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