1. Replacement Reactions

2. What happens to ionic compound in water?

3. Ionic Compounds When ionic compounds dissolve they become aqueous
The ion separate and are free to move about in the water
The separation of ions is very important to remember

4. Predict the possible products
Mg+ Fe(NO3)3 
Cu + Fe(NO3)3 
Fe + Mg(NO3)2
Fe + Cu(NO3)2

5. Lets see what happens Mg+ Fe(NO3)3  Cu + Fe(NO3)3  Fe + Mg(NO3)2
No reaction

6. Why did this happen
In order for a single replacement reaction to occur the element must be more reactive than the element that it will replace
Mg is more reactive than Fe, so we saw a reaction
Cu is less reactive than Fe, so we saw no reaction

7. Activity series
Activity series list the elements in order of reactivity
We can use the chart to predict if a reaction will occur

8. Double replacement reactions
Two ionic compounds react and for two new ionic compounds
In order for a DR reaction to occur one of the new compounds formed must be
A solid
A gas
Water

9. How do we know what is solid
Solubility charts let us know what will dissolve and what will form a solid

10. Lets do an example
What will happen when we mix solutions of silver nitrate and sodium chloride
AgNO3 + KCl 
The “possible products are …..
AgNO3 + KCl  AgCl + KNO3
Is either one a solid?
Yes, AgCl is insoluble, so it is solid

11. Lets do another example
What will happen when you mix solutions of potassium chloride and copper II nitrate
KCl + NaNO3
The possible products are….
KCl + Cu(NO3)2  NaCl and KNO3
Are either the products solids
Neither products are solids they are both aqueous
So…… No reaction

12. Equations
Molecular equations – show the complete chemical formulas. Does not indicate ionic character
Complete ionic equation – shows all ions. Actually how the particles exist in the solution
Net Ionic Equations- show only the ions and molecules involved in the actual reaction

13. Rules
When writing ionic equations, you must remember that solids, gases or water do not dissociate
Spectator ions – ions that appear on both sides of the equation. They have very little to do with the chemical reaction

14. Steps for Writing Ionic Equations Know these steps
Write the balanced molecular equation (balanced chemical equation)
Break every thing down into its ions EXCEPT the solid, gas, water, or(complete ionic equation)
Cross out everything that is the same on both sides (spectator ions)
Write what is left (net ionic equation)

15. Example
Write the balanced chemical equation, the complete ionic equation, and the net ionic equation for the reaction between lead (II) nitrate and potassium iodide

16. Example Write the balanced chemical equation
Pb(NO3)2(aq) + 2 KI (aq)  PbI2 + 2 KNO3(aq)
You MUST identify the solid, gas, or water
Pb(NO3)2(aq) + 2 KI (aq)  PbI2 (s) + 2 KNO3 (aq)
Balanced chemical equation

17. Example
Now break every thing except the solid, gas, or water into its ions
Remember ions are things with charges
Everything will be broken down into one positive charge and one negative charge

18. Example Pb(NO3)2(aq) + 2 KI (aq)  PbI2 (s) + 2 KNO3(aq)
Pb+2 + 2NO K I -1  PbI2 (s) + 2K+1 + 2NO3-1
Complete ionic Equation

19. Eliminate the spectators
Pb(NO3)2(aq) + 2 KI (aq)  PbI2 (s) + 2 KNO3(aq)
Pb+2 + 2NO K I -1  PbI2 (s) + 2K+1 + 2NO3-1
Now write what is left
Pb I -1  PbI2 (s)
Net ionic equation