1. Unit 9 -- Solutions
Lundquist

2. Unit 9.1
Solutions and Solubility Curves

3. Solutions Mixture of substances (2+)
State of matter depends on the solvent
Solute: substance that is dissolved
Solvent: substance that does the dissolving

4. 9.1 Note Quiz Questions 1. 2.

5. All about attraction!

6. Properties of solutions
Homogeneous
Cannot be filtered
Transparent
Can be separated by evaporating the solvent

7. 9.1 Note Quiz Questions 3.

8. Solubility Soluble – if a substance can be dissolved in the solvent
AKA: Miscible
Insoluble – if a substance can not be dissolved in the solvent (< 1% )
AKA immiscible
Solubility -- How much solvent can be dissolved in a solute at a given temp and pressure

9. Like Dissolves Like! Polar compounds dissolve polar compounds
Water is the universal solvent because of its polarity
Non-polar compounds dissolve non-polar compounds
Benzene can dissolve plastic because both are non-polar

10. Solvation

11. 9.1 Note Quiz Questions 4. 5.

12. Rate of solubility
Since solubility occurs when molecules collide, increasing the rate of collisions will increase how much quickly the solute dissolves
Stirring
Increasing solute surface area
Increasing temperature
Since the molecules of solvent have to move between the molecules of solute energy is absorbed (endothermic process)

13. Factors that effect solubility
Temperature
Effects solid solubility mainly
Direct relationship with solubility
Pressure
Effects gaseous solubility mainly
Solubility increases as pressure around the solute increases
Soda is bottled at a higher pressure, when opened it begins to effuse out.

14. Solubility curves
Graph assumes a 100g sample of water, if you had 200g just double the values
Different phases dissolve differently
Solids
Higher solubility at higher temp.
(+) slopes
Gases
Higher solubility at lower temps
(-) slopes

15. Solubility curves -think of it like a party
Saturated – on the line
“We’re out of seats, no one can come in till someone leaves.”
Unsaturated – below the line
Coach L’s usual party itinerary
“We got room come on it!”
To calculate how much more can fit in find out how much under the line you are on the Y-axis
Supersaturated – above the line
“I’ve hired a bouncer!”
Excess is precipitate
Solid falls out of solution
To calculate: find how much you are over on the Y-axis and subtract till you get to the line

16. p. 14 KNO3 at 70oC NaCl at 100oC NH4Cl at 90oC
In 50mL H2O
NaCl at 100oC
In 200mL H2O
NH4Cl at 90oC
Which is most soluble at 15oC?

17. p. 14
70g NaNO3 at 30oC
50g NH4Cl at 50oC
3. What is the solubility of KCl at 5oC

18. Do p use note p. 4

19. 9.1 Note Quiz 6. 7.

20. 9.1 Note Quiz Questions 9. 8.

21. 9.1 Note Quiz
10.

23. Unit 9.2
Units of Concentration
Dilutions

24. 𝑀= 𝑚𝑜 𝑙 𝑠𝑜𝑙𝑢𝑡𝑒 𝐿 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛
Molarity
Concentration – how much stuff do you have in a set space
Molarity -- Concentration of molecules in a solution
You are usually given grams so you have to convert
You are usually given milliliters so you have to convert
𝑀= 𝑚𝑜 𝑙 𝑠𝑜𝑙𝑢𝑡𝑒 𝐿 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛

25. Practice
What is the molarity of a solution of 100mL of water and 36g of hydrochloric acid
How many grams of sugar (C12H22O11) are in 500mL of a 0.5M solution?

26. 9.2 Note Quiz Questions 1. 2. 3.

27. 9.2 Note Quiz Questions 4. 5.

28. 9.2 Note Quiz Questions 6. 7.

29. Making solutions

30. Do p. 8-10
SKIP #6 & #8 on p. 10

31. Other Units of concentration
Molarity (M)
Molality (m)
𝑀= 𝑚𝑜 𝑙 𝑠𝑜𝑙𝑢𝑡𝑒 𝐿 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛
Volume can change with temperature (Charles Law)
Not good for solutions that fluctuate in temp.
𝑚= 𝑚𝑜 𝑙 𝑠𝑜𝑙𝑢𝑡𝑒 𝐾 𝑔 𝑠𝑜𝑙𝑣𝑒𝑛𝑡
Not dependent on temperature since MASS never changes
Good for temperature changes
What is the molality of a solution made from 100.mL water and 5.0g NaCl?

32. Other Units of concentration
Mole Fraction (c)
Percent by Mass (%)
𝜒= 𝑚𝑜 𝑙 𝑠𝑜𝑙𝑢𝑡𝑒 𝑚𝑜 𝑙 𝑠𝑜𝑙𝑢𝑡𝑒 +𝑚𝑜 𝑙 𝑠𝑜𝑙𝑣𝑒𝑛𝑡
Same thing we used in Dalton’s Law
Based off number of moles
What is the concentration of a solution made from 0.4 mol benzene in 1.6mol naphaline?
%= 𝑚𝑎𝑠 𝑠 𝑠𝑜𝑙𝑢𝑡𝑒 𝑚𝑎𝑠 𝑠 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 ×100
MOST COMMON in the real world
What mass of sugar is in 25og of 10% sugar water?

33. Other Units of concentration
Parts per Million (ppm)
𝑝𝑝𝑚= 𝑚𝑎𝑠 𝑠 𝑠𝑜𝑙𝑢𝑡𝑒 𝑚𝑎𝑠 𝑠 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 × 10 6
Based off mass percent
A solution is made of 20g salt and 100mL water, what is the ppm salt?
The SOL only tests M, however I require you to know: M m % c

34. Dilutions Adding the solvent to lower the concentration of the solute.
The amount of solute (mols) remains unchanged
LOWERS concentration (M)

35. Dilutions 𝑚𝑜𝑙 𝐿 1 𝐿 1 = 𝑚𝑜𝑙 𝐿 2 𝐿 2 𝑀 1 𝑉 1 = 𝑀 2 𝑉 2
Since the number of Moles doesn’t change when we change the volume we can find the new concentration with the following formula
𝑚𝑜𝑙 𝐿 1 𝐿 1 = 𝑚𝑜𝑙 𝐿 2 𝐿 𝑀 1 𝑉 1 = 𝑀 2 𝑉 2

36. Performing Dilutions

37. Practice
What volume of a 3.0M KI solution would you use to make 0.300L of a 1.25M KI solution?
How many milliliters of a 5.0M H2SO4 stock solution would you need to prepare 100mL of a 0.25M H2SO4? How much water would you need to add to your 5.0M stock solution to produce 100mL of 0.25M H2SO4
If you dilute 20.0mL of a 3.5M solution to make 100mL of solution, what is the molarity of the dilute solution?

38. 9.2 Note Quiz Questions 8. 9.
10.

39. Do p. 11 & 12

40. Unit 9.3
Colligative Properties
Types of Solutions

41. Colligative Properties of solutions
Physical properties of solutions that are effected by the number of particles in solutions but NOT by the identity of dissolved particles in solution.
Ionic compounds have a greater effect on colligative properties then covalent compounds
Dissociation factor(df) or Van’t Hoff Factor (i)
How many ions does the compound form?
For non-electrolytic compounds (covalent compounds) the df is always one (1).
For ionic compound the df is the number of ions that form that compound.
Effect:
Vapor pressure
Boiling point
Freezing point

42. Vapor pressure
number of solvent particles exposed to surface, less enter gas phase
Lower vapor pressure

43. Boiling Point
Increases because fewer particles on the surface are contributing to the vapor pressure (takes more energy to raise the vapor pressure)
Dependent on vapor pressure
Kb = difference in temp. of solution
and pure solvent

44. Freezing point When kinetic energy can no longer overcome attraction
Decreases because solute particles get in the way of attractive forces, cause the more energy to need to be lowered for phase change

45. Calculating the effect of solute on freezing points and boiling points
Where DT = change in BP or FP (°C) m = molality ( 𝑔 𝑘𝑔 ) or concentration of solution i = dissociation factor K = constant for solvent (given)
Boiling Point
𝛥𝑇=𝑚 𝐾 𝑏 𝑖 𝐵𝑃=𝐵 𝑃 ∘ +𝛥𝑇
Freezing Point
𝛥𝑇=𝑚 𝐾 𝑓 𝑖 𝐹𝑃=𝐹 𝑃 ∘ −𝛥𝑇

46. What is the freezing point of a 0
What is the freezing point of a 0.40m solution of sucrose in ethanol, if ethanol’s normal freezing point is °C? (Kf = 1.99 °C/M)
DT = m(df)K
m = 0.40m
i = 1
K = 1.99 °C/m
DT = 0.40M (1) 1.99°C/m
DT = 0.796°C
New freezing point = °C – 0.796°C = °C

47. Do p

48. Types of Solutions Solutions Colloid Very small particles
Light passes through it easy (transparent)
Large particles
Scatters light passing through it
Will NOT settle

49. Types of Solutions Suspensions VERY large particles
Will settle out over time

50. THE END Test NEXT PERIOD! 35 MC you will need to 21 to get a 100
Multiple Choice homework due NEXT PERIOD!
Test NEXT PERIOD!
35 MC you will need to 21 to get a 100
NO FRQ