3.48. Properties of Solutions http://www.ck12.org
Summary
- When a solute dissolves in a solvent, it changes the physical properties of the solvent.
- A solute generally lowers the freezing point of a solvent, which is called freezing point depression. For
example, spreading salt on an icy road melts the ice. - A solute generally raises the boiling point of a solvent, which is called boiling point elevation. For example,
adding antifreeze to the water in a car radiator prevents the water from boiling.
Explore More
Do the animated experiment at the following URL. First, select water as the solvent and sodium chloride as the
solute. Then, determine the boiling and freezing points of a solution containing different masses of the solute, while
holding the mass of solvent constant at 200 grams. Test at least five different masses of the solute, and record your
results in a data table. Finally, write a brief summary of what your data reveal about boiling point elevation and
freezing point depression of saltwater solutions. http://group.chem.iastate.edu/Greenbowe/sections/projectfolder/f
lashfiles/propOfSoln/colligative.html
Review
- What is freezing point depression?
- Give an example of boiling point elevation.
- Assume you are going to boil water to cook spaghetti. If you add salt to the water, how will this affect the
temperature at which the water boils? How might it affect the time it takes the spaghetti to cook?