Colligative Properties

[xylashellx]

hello chemistry inclined people...

so i was just doing a topscore question on osmotic pressure (number 61 on test 2) and i got the wrong answer because NaCl dissociated into twice the amount of moles. can anyone give me a brief explanation about when things will give you twice the amount of moles and what problems i would have to use that in(besides osmotic pressure obviously)...thanks

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[r0entgen]

hello chemistry inclined people...

so i was just doing a topscore question on osmotic pressure (number 61 on test 2) and i got the wrong answer because NaCl dissociated into twice the amount of moles. can anyone give me a brief explanation about when things will give you twice the amount of moles and what problems i would have to use that in(besides osmotic pressure obviously)...thanks

well, osmotic pressure = iMRT

so basically, you need the colligative molarity...

"i" is the van't hoff factor

i=1 for a covalent compound
i=2 for an ionic salt like NaCl
i=3 for an ionic salt like CaCl2
...etc...

 

[xylashellx]

thanks that helps alot