1. Chapter 15.2 Homogeneous Aqueous Systems
Chapter 15.3 Heterogeneous Aqueous Systems

2. Chapter 15.2 Homogeneous Aqueous Systems
Chapter 15.3 Heterogeneous Aqueous Systems

3. Learning Objectives
Understand the “s” words and how they are different from each other (solution, solvent, solute)
Understand the process of solvation of ions
“Like dissolves like” and the difference between polar and non-polar molecules when it comes to solvation.
Electrolyte versus non-electrolyte
Solutions vs. colloids vs. suspensions

4. Solution (aq) – water that contains dissolved substances Solvent – The dissolving medium of the solution (water in this chapter) Solute – The solid that gets dissolved Solvent plus solute = solution

6. When a substance becomes solvated by water, we say it is soluble in water
Chemists use the axiom “like dissolves like”:
Polar substances tend to dissolve in polar solvents.
Nonpolar substances tend to dissolve in nonpolar solvents.

9. All ionic compounds are electrolytes because they break apart into ions when added to water

10. The next part of the textbook is about hydrates …
we will skip for the upcoming TWIZ
We did do a lab where we heated a hydrate CuSO4 . 5H2O and determined how much water was released in moles.

11. It is a type of homogeneous aqueous system known as a colloid.
The JELL-O mystery … what the heck is it?
It is a type of homogeneous aqueous system known as a colloid.
JELL-O is a kind of strange substance which is a colloid. JELL-O is made from water with flavorings, sweetener, and gelatin mixed in. Gelatin is made from a protein called collagen which is the main protein in cartilage, the flexible material that forms your outer ear and nose. When JELL-O is added to hot water, the long collagen molecules separate from each other and mix throughout the water. But when this mixture is cooled, the collagen molecules link up with each other in a different way, forming a 3-dimensional network. Water molecules get trapped in the network and help give JELL-O its more wiggly characteristics.  (adapted from ACS website)
More info about colloids

12. Particles are 1 nm – 1000 nm

13. Example of a emulsion while doing chemistry

14. Tyndall Effect Colloidal suspensions can scatter rays of light
This phenomenon is known as the Tyndall effect

16. Summary Type of Aqueous System Can you see the solute? Particle Size
Does it scatter light?
Solution
Homogeneous (Evenly dispersed) No
< 1 nm
Colloid
Between nm and 1000 nm
Yes
Suspension
Heterogeneous (Unevenly dispersed)
> 1000 nm
Depends on size of particles and how they are dispersed