Concentration
Changing Concentration
| concentration solution | a lot of solute dissolved in a certain amount of solvent. |
| dilute solution | only a little solute
dissolved in certain amount of solvent.
adding water to a juice concentrate making a more dilute solution |
Measuring Concentration
to measure concentration
you compare the amount of solute to the total amount of solution
measure the mass in grams
measure the volume in milliliters or liters.
measure as a percent of solute in solution by mass or volume
Solubility
| solubility |
|
| unsaturated solution | more can be added
to the solution
-adding sugar to lemon juice, the sugar dissolves as you stir. |
| saturated solution | when more is
added, it does not dissolve
-continually adding sugar, the sugar starts to settle at the bottom. |
Working
with solubility
how much solute can be dissolved before a solution becomes saturated.
solids, solubility is for a particular temperature under a certain pressure
EXAMPLE: 100 grams of water will dissolve 6.9 grams of
baking soda at sea level.
Using
solubility
a substance can be identify by its solubility because it is a characteristic
property of matter.
Factors Affecting Solubility
Pressure
increasing the pressure increases the solubility of gases.
example of scuba divers and nitrogen in the blood stream on page 265
Solvents:
non compatibility
oil and vinegar
like dissolves like
ionic and polar compounds usually dissolve in polar solvents
non polar compounds do not usually dissolve in polar solvents
Temperature
for most solids, solubility increases as the temperature increases
gasses becomes less soluble in a liquid
soda tastes "Flat".
warm soda water contains less carbon dioxide gas
supersaturated solution
more dissolved solute than is predicted
when a crystal of the solute is dropped into a supersaturated solution,
the extra solute will come out of the solution (illustration on p.
269)