No.
Did Bob P respond? I don't want to redo what he has already done? If not I can get you started, perhaps right this time.
How many grams of water would you add to 1.00 kg of 1.48 m CH3OH(aq) to reduce the molality to 1.00 m CH3OH. Use two sig figs.
I get 4.8 * 10^2 grams and its not right. I want to put this up here again to see if there are any errors that could have possibly been made.
(Putting this back up cause of too many questions. To Doctor Bob and Pursley)
If its actually fewer, would the answer actually be 4.8 * 10 ^-2 instead?
3 answers
Nope he has not responded
OK. Think along these lines.
If we have 1.48 m CH3OH, that is 1.48 moles CH3OH in 1000 g water. So the solution contains 1000 g for the water + (1.48*32 = about 47.36 g CH3OH but you need to confirm that the molar mass CH3OH is 32. I just used this number off the top of my head). So the 1.48 m CH3OH solution actually has a mass of 1000 g + 47.36 g or 1047.36 grams). Now if we take a 1 kg sample of that solution, we get
1.48 moles x 1000/1047.36 = 1.41308 moles (which I know is too many places but you can always round at the last--and should). So now you want to know how much water must be added to the kg of solution (remembering that all of it is NOT water). I think something like 458.3 grams of added water will do it but you can't have that many s.f.
If we have 1.48 m CH3OH, that is 1.48 moles CH3OH in 1000 g water. So the solution contains 1000 g for the water + (1.48*32 = about 47.36 g CH3OH but you need to confirm that the molar mass CH3OH is 32. I just used this number off the top of my head). So the 1.48 m CH3OH solution actually has a mass of 1000 g + 47.36 g or 1047.36 grams). Now if we take a 1 kg sample of that solution, we get
1.48 moles x 1000/1047.36 = 1.41308 moles (which I know is too many places but you can always round at the last--and should). So now you want to know how much water must be added to the kg of solution (remembering that all of it is NOT water). I think something like 458.3 grams of added water will do it but you can't have that many s.f.