Chemistry of Water: Boiling Time Comparisons

[yeshli2nuts]

i had this problem for homework and i need some help. if i had 1 cup of water compared to 1 cup of water with tablespoon of salt disolved in it, which would take longer, by how much time, and why to bring to a boil? and how about 1 cup of water with a tablespoon of sugar compared to the other two?
thanks a lot.

 

[GCT]

You need to have your thoughts first instead of expecting us to do your homework for you. What concept does this question relate to?

 

[Guillermo]

Any solvent with dissolved substance boils higher and freezes lower then the pure one.

G

 

[Artermis]

Try thinking about what needs to happen for liquid molecules to escape the liquid state and be vaporized into gas. Now, what happens if something is dissolved in it? Try writing out the chemical equation for the dissolution of a salt. Namely, how does the solute affect the new solvent compared to the pure solvent?

 

[wangasu]

Because the solute(salt)-solvent(liquid molecule like water) interactions are stronger than liquid intermolecular interactions, some cluster-like structures form in the solution. The stronger trap of the liquid molecule prevent its escape, and leads to the rise of boiling point. Generally, viscosity of very dilute solution increases with concentration of salt. but at medium and higher concentration ranges, the relation is not so simple.

 

[GCT]

additional hint: van't hoff factor and perhaps consider the much more ordered arrangement of water in solvating the salt in comparison to the sugar.