1. Solutions

2. Characteristics of Solutions
Forming Solutions
Solubility

3. Forming Solutions Solution Aqueous solution Homogeneous solutions
Uniformly mixed
Solute + Solvent
Solute: what is being dissolved
Solvent: the substance that the solute is dissolved into
Aqueous solution
Solvent is water

4. Solubility “Like Dissolves Like”
a given solvent can dissolve solutes that have similar polarities
Polar dissolves in polar (So things like water dissolve get pulled apart)
Non-polar dissolves in nonpolar (like oily organic stuff)

5. Different Solutes Ionic Substances Have a dipole
Ions are attracted to the polar water molecules
Can dissolve in water
Polar substances
Charged poles are attracted to the polar water molecules
Nonpolar substances
Do not have a dipole
Cannot dissolve in water

6. Types of Solutions
Solid
Alloys
Brass
Liquid
Sea water
Gas
Air

7. Solvation
Process of solvent particles surrounding solute particles to create a solution
The attraction between the solute and solvent overcome the attraction between the particles

8. Ionic vs. Covalent Substances connected by intermolecular forces
Substances connected by electrostatic attractions
Solvent break apart the crystalline solid form by the ions
Breaks into individual ions
Substances connected by intermolecular forces
Hydrogen bonding
Dipoles
Solvent overcomes intermolecular forces to break apart the “clump”
Breaks into molecules

9. Electrolytes vs. Non-Electrolytes
Electrolytes: solutions that conduct an electric current
Acids, bases, and salts dissolve in water to form conducting solutions
Non-electrolytes→ solutions that do not conduct an electric current

10. Solution Composition Unsaturated Saturated Supersaturated
More solute can be added to solvent at that temperature
Saturated
The maximum amount of solute is dissolved in the solvent at that temperature
Supersaturated
The amount of solute dissolved into the solvent is OVER the maximum amount at that temperature

11. Describing Solutions Dilute Small amount of solute is dissolved
Concentrated
Large amount of solute is dissolved
Concentration [ ] shown sometimes as brackets
A measure of the amount of solute in a given amount of volume

12. Factors Affecting Solubility
Solubility: the ability to dissolve
Surface area
Stirring
Temperature

13. Surface Area / Stirring
Amount of area on the surface of a substance/object
More surface area = faster rate
More stirring = increase in rate
Break away old particle exposing new one to repeat dissolving process

14. Average Kinetic Energy
Temperature
Average Kinetic Energy
High temperature = Faster rate
Causes solvent particles to move faster
Most solids are more soluble at high temperatures
Most gases are more soluble at low temperatures

15. Properties of Solutions
Homogeneous
Light goes through them
Particles will NOT come out of solution
They will go through fine filters

16. Calculations Parts Per Million or or Parts Per Billion or Mg of solute
Cppm =
L of solution
Parts Per Billion or

17. Percentages Mass percent: Percents of the solution by mass
Mass-volume percent: mass of solute in grams per 100mL of solvent
Volume -volume percent: volume of solute in grams per 100mL of solvent
Mass of solute (g)
x 100
Mass of solution (g)
Mass of solute (g)
x 100
Volume of solution mL
Volume of solute
x 100
Volume of solution

18. Solubility Curves
Curve that shows how many grams of solute can be dissolved into a given amount of solvent at different temperatures.
How to Read a Solubility Curve
Find the temperature on the (x-axis)
Move up the substance line (curve)
Slide over to the gram amount

19. Solubility Curves Continued
If the amount is ABOVE the curve the solution is supersaturated
If the amount is BELOW the curve the solution is unsaturated
If the amount is RIGHT ON the curve the solution is saturated

20. Types of Soulubity Problems
Am I saturated, unsaturated, or supersaturated ?
How much more/less solute will be in solution if I raise/lower the temperature ?
How much solute would saturate a solution of a DIFFERENT volume than the solubility curve ?

21. Solubility Problem of a different Volume
Steps to solve
Find saturation amount from the curve
Make a table of values
Setup a proportion using the information from the problem and curve
Solve

22. Molarity The amount of mole per given volume of solutions
Measurement of concentration
Indicated by M
Units are mol/L

23. Molarity by Dilution M1V1=M2V2
Dilute: to add more solvent without adding solute
To determine the concentration of new solution
M1V1=M2V2
M: Molarity defined as “moles per liter”
V: Volume defined as “liters”

24. Colligative Properties
physical properties of solutions that are affected by the number of solute particles but not the identity of dissolved solute particles
Vapor Pressure
Boiling Point elevation
Freezing point depression

25. Vapor Pressure
the pressure exerted in a closed container by liquids particles that have escaped the liquid’s surface & entered the gaseous state
Lowers Vapor Pressure
Adding a nonvolatile solute
Less molecules of the solvent (water) are able to evaporate which lowers the VP

26. Boiling Point
temperature at which the vapor pressure equals the atmospheric pressure in order for the solvent to escape the liquid state
Boiling Point Elevation
the temperature difference between a solution’s boiling point and a pure solvent’s boiling point
Greater number of solute particles in solution the greater the boiling point is elevated
Directly proportional relationship

27. Freezing Point
The temperature when a solution goes from a liquid to a solid
Particles become more organized
Particle do not have enough KE to overcome their intermolecular forces
Freezing Point Depression
Difference in temperature between its freezing point and the freezing point of its pure solvent
Particle interfere with the IMFs which lowers the FP
The more particles of solute the lower the FP depresses

28. Molality Molality is used to calculate FP and BP problems
Allows for other solvents to be used more easily

29. Colligative properties problems
TB = (KB) (m) (i)
TF = (KF) (m) (i)
TB: Change in boiling point
KB: Boiling point constant
m: Molality
i: number of particles (Van Hoff)
TF: Change in freezing point
KF: Freezing point constant i: number of particles (Van Hoff)

30. Steps to solve Calculate the molality
Determine how many parts the solute breaks into
Use the colligative properties equation
Is it freezing ?
Is it boiling?
Solve for change in temperature
add/subtract from original BP/FP
BP adding
FP subtraction

31. Solubility Review Not all compounds are soluble
Completely soluble
Slightly soluble
insoluble
Must check the solubility chart
Solvent is water

32. Process to solve Write a balanced equation with phase indicators
Balance for charge (subscripts)
Balance for mass (coefficients)
Determine if there is an insoluble product
Separate all soluble compounds
Do not separate insoluble compounds
Cross out spectator ions
Re-write the equations with ions/compound that contribute to the reactions 29

33. Sample Problem Ni 2+(aq) +2(OH 1-)(aq) → Ni(OH)2(s) 2 2
____Ni(NO3) ____NaOH → _____ Ni(OH) _____ NaNO3
Ni 2+(aq) +2(NO3)1-(aq)+2Na1+(aq)+2(OH 1-)(aq) → Ni(OH) Na1+(aq)+ 2(NO3)1-(aq)
Ni 2+(aq) +2(OH 1-)(aq) → Ni(OH)2(s)
(aq)
(aq)
(s)
(aq)
(s)
(s) 30