Mrhyde

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Apr 13, 2015
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Gen Chem Dat Destroyer Question number 223

This problem I was confused on because I saw no kg of solvent anywhere then,

When I looked at the explanation I understand everything except the following detail makes no sense to me:


DeltaT = iKm

and m is "molal" which is simply : moles solute/ kg solvent

so in the answer explanation I see that they put .6 liters in the denomenator for where kg solvent should be. This must be wrong. Because the only time this would be true is if we were using Molarity which is moles solute/Volume litters of solution ...... but for these temperature problems we always use molal and not Molarity ? is this a mistake in the problem ? They even wrote molal correactly by putting it as kg solvent yet on the next step when it was time to plug in a number they plugged in litters instead ?
 

orgoman22

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Gen Chem Dat Destroyer Question number 223

This problem I was confused on because I saw no kg of solvent anywhere then,

When I looked at the explanation I understand everything except the following detail makes no sense to me:


DeltaT = iKm

and m is "molal" which is simply : moles solute/ kg solvent

so in the answer explanation I see that they put .6 liters in the denomenator for where kg solvent should be. This must be wrong. Because the only time this would be true is if we were using Molarity which is moles solute/Volume litters of solution ...... but for these temperature problems we always use molal and not Molarity ? is this a mistake in the problem ? They even wrote molal correactly by putting it as kg solvent yet on the next step when it was time to plug in a number they plugged in litters instead ?
You fell into a " bear trap "....600ml of water is also 600 grams of water since water density is 1 g/ml........ With that in mind......ml is equal to grams here...beyond that....you have a smooth ride ahead !!!!

Hope this helps

Keep up the good work!

Dr. Romano