Chemistry Solutions -- Solute/Solvent; Soluble/Unsoluble; Miscible/Immiscible; Polar/Nonpolar

1. Solutions
Unit 9: Solutions

2. What are solutions?
• Solutions are homogeneous mixtures
–Look the same throughout
• Combined physically (not chemically)
• You CAN separate by physical means
using filtration, distillation, or
evaporation.
• Examples: Cola, Gasoline, Cleaners

3. What are solutions?
• Solutions have two parts:
–Solute
–Solvent
Solute
Solvent

4. What are solutes and solvents?
• The solute is the substance being
dissolved and it is always present in
smaller amounts
• The solvent is doing the dissolving
and is always present in larger
amounts
–AKA the dissolving agent

5. What are solutes and solvents?
• Example: Kool-Aid
• What is the solute?
–Kool-Aid Powder because it is being
dissolved and there is less of it
• What is the solvent?
–Water because it is doing the dissolving and
there is more of it
Solute + Solvent = Solution

6. What are the types of solutions?
• Solutions can be solid, liquid, or gas
based on the solvent’s state of matter
because there is more of it!
–Example: Air is a solution with the solvent
being nitrogen and solute being oxygen
because ~75% of air is nitrogen and ~24% of
air being oxygen
• Not all substances can form solutions!
• If a solid solute can dissolve in a liquid, it
is called soluble
–Kool-aid is soluble in water

7. What are the types of solutions?
• If two liquids dissolve in each other they are
miscible
– Food coloring is miscible in water
• If a solid solute cannot dissolve in a liquid, it
is insoluble
– Sand is insoluble in water
• If two liquids cannot dissolve in each other,
they are immiscible
– Oil and water are immiscible
– Meniscus will be visible if two liquids are
immiscible!

9. What are the steps of solution formation?
1. Solvation: the solvent particles
completely surround solute particles
– Called hydration if solvent is water
2. Dissociation: ions are pulled apart by
solvent and seem to “disappear”

11. How do we know if something is soluble?
• The substances involved in making a
solution are either polar or nonpolar
• If a substance is polar, it has regions
of opposite charge
–Ionic compounds are usually polar

12. How do we know if something is soluble?
• If a substance is nonpolar, it does not
have regions of opposite charge
–Covalent compounds are usually
nonpolar
• EXCEPTION: Water is covalent and
polar
• Nicknamed “universal solvent”
because of its unique solution
properties

13. Practice
• Are the following polar or nonpolar?
• NaCl
–Polar – Ionic
• KBr
–Polar – Ionic
• CH4
–Nonpolar – Covalent

14. How do we know if something is soluble?
• Rule: “Like Dissolves Like”
• Polar solvents dissolve polar solutes
• Nonpolar solvents dissolve nonpolar
solutes
• Polar solvents WILL NOT dissolve
nonpolar solutes