Learning Goals 3.7
Learning Goals 3.8
Textbook Reading
“Chemistry: 2e” Second Edition, 2014. A digital version of the textbook will be available here.
Read: Chapter 1 - Section 2 (you read this before)
Chapter 3 - Section 3
Review Figure 11.7
In a suspension, the particles do not dissolve.
Other examples include milk (suspension) and paint (mechanical mixture)
A solution will never separate so long as the pressure and temp remain constant.
So we have a constant concentration throughout the sample
A solute is something “U” put into the solvent.
Think of making a powdered drink mix like lemonade or hot cocoa…
Watered-down lemonade
Concentrated lemonade
“Super Saturated” lemonade with powder on the bottom of the cup.
Star that second bullet point! Equilibrium is dynamic (it never stops)
Add this to your notes please:
Soluble: Able to dissolve to a point (reach saturation) (ex. Sugar water)
Miscible: Able to dissolve in any proportion (never become saturated) (ex. Alcohol %)
Miscible liquids have similar IMF properties (like dissolves like - polar dissolves polar - nonpolar dissolves nonpolar)
The IMFs between solute and solvent have to be ≥ IMFS between pure solute or pure solvent molecules.
Methanol dissolves in water due to forming H-bonds between each other.
Miscible in all proportions means you could have a little methanol in a lot of water or a lot of methanol in a little water and they still dissolve.
1 + 1 ≠ 2
Differences in IMF can cause the new solution’s volume to be a little larger or smaller than the sum of the volume combined.
Volumes don’t always add up
This is hexanol (6C alcohol) dissolved in water.
Miscibility depends on solute size and IMF
Alcohol with 1-2 Cs are soluble and miscible
Alcohol with 3-6 Cs are soluble but not miscible
Alcohol with 7C+s are not soluble or miscible
These are two miscible, nonpolar substances even though there is a polar end to hexanol
Polar molecules also experience dispersion forces
CO2 and O2 are nonpolar… but they dissolve by dipole induced-dipole forces.
Interesting!
There is always H2(g) in oil and natural gas.
As oil and natural gas travel down pipelines, that H2(g) can enter the iron pipes to become an interstitial alloy (making the pipe brittle). To prevent pipes from breaking, chemical engineers remove as much H2 as possible.
Oxygen can dissolve in copper making the copper nonconductive. So copper wires must be cast in an oxygen-free environment.
Added carbon creates directions bonds in the interstitial alloy, strengthening the iron (creating steel).
Molarity = M
Moles = n
Liters = L
Molarity = M = n / L
Moles = n
Liters = L
Plan:
Grams → moles
mL → L
Then divide moles/L
Molarity = M = n / L
Moles = n
Liters = L
Plan:
Grams → moles
mL → L
Then divide moles/L
Molarity = M = n / L
Moles = n
Liters = L
Plan:
Grams → moles
mL → L
Then divide moles/L
Let’s rearrange the problem!
M = n/L
Or
L = n/M
Plan:
Moles / M
then mL to L
Let’s rearrange the problem!
M = n/L
Or
L = n/M
Plan:
Moles / M
then mL to L
Let’s rearrange the problem!
M = n/L
Or
L = n/M
Plan:
Moles / M
then mL to L
n/M
Let’s rearrange the problem!
M = n/L
Or
L = n/M
Plan:
Moles / M
then mL to L
Time for a dilution!
Original Solution is 1.25 M NH3
New Solution I want to make is 100.0 mL and 1.00 M
Time for a dilution!
Original Solution is 1.25 M NH3
New Solution I want to make is 100.0 mL and 1.00 M
Time for a dilution!
Original Solution is 1.25 M NH3
New Solution I want to make is 100.0 mL and 1.00 M
Time for a dilution!
Original Solution is 1.25 M NH3
New Solution I want to make is 100.0 mL and 1.00 M
Time for a dilution!
Original Solution is 1.25 M NH3
New Solution I want to make is 100.0 mL and 1.00 M
I already know one mole fraction!
Learning Goals 3.7
Learning Goals 3.8
Homework
1
4
5
8
9
11
14
17 (Assume a 100 g sample)