1. Double Replacement Reactions Ionic Cmpd(aq) + Ionic Cmpd(aq)
Predicting Reaction Occurrence

2. What does it mean to be dissolved?
When an Ionic Compound dissolves, it dissociates into separate ions K Cl - +

3. What causes an ionic cmpd to dissolve?
Ionic Compound are held together by the electrostatic attraction of opposite charges K + Cl -
Opposites Attract
Attraction of Opposite Charges holds compound together

4. What causes an ionic cmpd to dissolve?
The charged ends of the water molecules are also attracted to the charged ions and “pull” the oppositely charged ions apart - + - + K + Cl -
Oxygen side is negatively charged
Hydrogen side is positively charged

5. Two Ways to Write Saltwater
Na+
Cl-
Na+
Cl-
Formula: NaCl(aq)
Ionic: Na+ + Cl-
Is this the same
as NaCl(l) ?

6. + NaCl(aq) MgSO4(aq) Na+ + Cl- + Mg+2 + SO4-2 Formula: Ionic: Na+ Cl-

7. Mg+2
Na+
Cl-
SO4-2
Cl-
Na+
Mg+2
SO4-2

8. Will These
Combine?
Mg+2
Na+
Cl-
SO4-2
Cl-
Na+
Mg+2
SO4-2

9. Will These
Combine?
Mg+2
Na+
Cl-
SO4-2
Cl-
Na+
Mg+2
SO4-2

10. Why did they bounce off each other?
MgCl2 is soluble,
so it stays dissolved
Why did they
bounce off
each other?
Will These
Combine?
Mg+2
Na+
Cl-
SO4-2
Cl-
Na+
Mg+2
SO4-2

11. Na2SO4 is soluble, so it stays dissolved Will These Combine? Mg+2 Na+
Cl-
SO4-2
Cl-
Na+
Mg+2
SO4-2

12. NaCl(aq) + MgSO4(aq) No Rxn All combinations are soluble Mg+2 Na+ Cl-

13. + CaCrO4(aq) MgSO4(aq) + Mg+2 + SO4-2 Ca+2 + CrO4-2 Formula: Ionic:

14. Mg+2
Ca+2
CrO4-2
SO4-2
CrO4-2
Ca+2
Mg+2
SO4-2

15. Will These
Combine?
Mg+2
Ca+2
CrO4-2
SO4-2
CrO4-2
Ca+2
Mg+2
SO4-2

16. Will These
Combine?
Mg+2
Ca+2
CrO4-2
SO4-2
CrO4-2
Ca+2
Mg+2
SO4-2

17. Why did they bounce off each other?
MgCrO4 is soluble,
so it stays dissolved
Why did they
bounce off
each other?
Will These
Combine?
Mg+2
Ca+2
CrO4-2
SO4-2
CrO4-2
Ca+2
Mg+2
SO4-2

18. + + CaCrO4(aq) MgSO4(aq) MgCrO4(aq) CaSO4(s) Spectator Ions Net Ionic
CaSO4 is insoluble,
so it forms a
___________
Mg+2 + CrO4-2 +
Ca+2 + CrO4-2
Mg+2 + SO4-2
Precipitate +
CaSO4(s)
Spectator Ions
Net Ionic
Equation
Ca+2 + SO4-2
CaSO4(s)
Will These
Combine?
Mg+2
Ca+2
CrO4-2
SO4-2
CrO4-2
Ca+2
Mg+2
SO4-2

19. Your Turn
Potassium phosphate(aq) + Barium chloride(aq)

20. Your Turn Include States in Formula Equation
DR Lab: For Questions #1-3
Include States in Formula Equation
Write Ionic and Net Ionic Equations

21. Useful Tip: Don’t let acids ‘bully’ you
HCl
Don’t let acids ‘bully’ you
To take away their bullying power, call them by their ‘nerdy’ name
Examples
For hydrochloric acid, HCl – call it ________________
For sulfuric acid, H2SO4 – call it _____________
Hydrogen chloride
Hydrogen sulfate

22. Double Replacement Rxns: Other Possibilities
Not all combinations that are insoluble are solids
Instead of Precipitates, we sometimes get
Insoluble Liquids
Gases
Blue “Cheat Sheet” has list of common insoluble liquids and gases

23. Example of Non-Precipitate
Potassium sulfite (aq) + nitric acid (aq) 
Hydrogen nitrate

24. Assignment
Get out Double Replacement Lab and Complete Pre-Lab Questions.
Write Ionic and Net Ionic Equations for all reaction
Complete back page on lab.
HW: Pages 13 & 14