Unformatted text preview: m stated ) m eff = 0.16 + (25/100)(0.16) m eff = 0.16 + (0.04) m eff = 0.20 m The effective molality is 25% higher than the stated. WARNING: This is the case for 1:1 electrolytes. 1:2 electrolytes will have MORE added on  double the %ionization to be exact. 1:3 electrolytes will have TRIPLE the %ionization amount added on to the stated molality. For any ratio of an electrolyte, n:m the formula will be: m eff = m stated + ( n+m1 )(%ion/100)( m stated ) Once you DO have the correct m eff you can put it into the various colligative property equations and get a more accurate measure of the colligative property. This is important! Finally, you can REVERSE this whole process and MEASURE the colligative property, and then backtrack to find the percent ionization. Back sure you can work problems BOTH ways. A few of your homework problems (and most likely an exam problem) require you to consider effective molality instead of the stated (or calculated) molality....
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 Spring '07
 Holcombe
 Chemistry, Physical chemistry, Mole, 0.20 m, 1 kilogram, 0.16 m, effective molality

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