Properties of Solutions
What is the definition of a solution?
Solute + Solution
According to Table F, (NH4)2CO3 is...
Soluble (anything with NH4 is soluble) in water.
State the two things that make a collision "effective" for dissolving
Proper orientation and proper energy
0.67M
(8.7g/26 g/mol) divided by (0.500L)
Consider CH4 and CaCl2. Which will dissolve in water? Which will dissolve in an organic solvent?
CaCl2 will dissolve in water (ionics dissolve in water)
CH4 will dissolve in organic solvents (nonpolars dissolve in organics)
In an aqueous solution, name the solvent and the term used for the substance being dissolved.
Solvent- water
Solute
A solution contains 35 g of solute per 100. g of water at 50 °C. According to Table G, this solution could be a supersaturated solution of which of the following:
KCl, NH4Cl, KClO3
KClO3
List three ways to increase the rate of dissolving a solid solute in wate
Stir it, heat it, grind it up!
How many moles of solute are in 5.000 L of a 2.0 M solution?
5.000L x 2.0M= 10. mole
An example of an electrolyte is:
C6H12O6, CCl4, CaCl2
CaCl2
Explain the difference between a concentrated solution and a dilute solution (use qualitative language).
Concentrated solutions have "a lot" of solute dissolved.
Dilute solutions have "a little" solute dissolved.
Define "unsaturated" on a solubility curve—what does a point below the curve mean for grams of solute per 100 g water?
Below the curve- unsaturated
Explain, in terms of collision theory, why increasing temperature increases the rate of dissolving for most solid solutes
Increasing the temperature causes more collisions and harder collisions, which results in more effective collisions.
If you dilute 75.0 mL of 0.50 M NaCl(aq) to a final volume of 150. mL, what is the new concentration?
(75.0mL) x (0.50 M) = (150. mL) x M2
M2= 0.25M
At standard pressure, the freezing point of an unsaturated LiF(aq) solution decreases when
1. it is stirred 2. more LiF is added 3. more water is added
2- more LiF is added (Colligative properties: freezing point decreases with increasing concentration of solute)
A solution of 0.010 M CaCl2 is a
heterogeneous mixture, homogenous mixture,
heterogeneous compound, homogeneous compound
homogenous mixture
2 x 40.0g= 80. grams.
For gaseous solutes dissolved in water, how does increasing temperature affect solubility. Why?
Increasing the temperature causes the gas to escape the liquid, and therefore decreases solubility.
A sample problem: 0.50 g NaBr is dissolved in 120.0 g water. What is the percent by mass? What is the concentration in ppm?
% by mass: [ (0.50 g) divided by (120.50g) ] x 100 = 0.42 %
PPM: [ (0.50 g) divided by (120.50g) ] x 1 000 000= 4100 ppm
How does the van’t Hoff factor affect the magnitude of freezing point depression for an ionic solute versus a nonelectrolyte solute of the same molarity?
An ionic solute has a larger van't Hoff factor and a larger freezing point depression (more particles dissolved than a nonelectrolyte solution of the same molarity).
A single crystal of CaCl2 is added to a solution of the salt. The single crystal sinks to the bottom the beaker, where there was already a small amount of solid. If there were no change in temperature, the original solution was
saturated
If 80 g of NaNO3 are added to 50 g H2O at 10 °C, is the solution is unsaturated, saturated, or supersaturated?
Supersaturated (note: 50. g, not 100. g of water)
What does removing the cap on a cold soda bottle under high pressure do?
Reducing the pressure allows the gas to escape the liquid- the soda goes flat when the gas escapes.
What is the volume of 18M H2SO4 is needed to make 500. mL of a 2.0M solution?
(18 M) V1= (500. mL) (2.0 M)
V1 = 56 mL
Which conditions result in the highest boiling point and lowest boiling for an aqueous solution?
0.5M C6H12O6 dissolved in 1.0L water
0.5M NaCl dissolved in 1.0L water
0.5M AlCl3 dissolved in 1.0L water
0.5M AlCl3 dissolved in 1.0L water
Highest van't Hoff factor, therefore most particles dissolved, therefore greatest BP elevation, lowest MP depression