1. Calcium phosphate reacts with sodium hydroxide
2. Write the complete balanced equation
3. If you start with 50 grams of calcium phosphate, how many grams of calcium hydroxide would be produced?
4. Take out your final exam study guide and work on practice problems

• Take out your final exam study guide and work on practice problems
• Set up for notes #19 and practice problems 19

• Separation of ions that occurs when an ionic compound dissolves in water
• Balance chemical equation for charge as well as for atoms.
• CaCl
2
(s) → Ca 2+ (aq) + 2 Cl (aq)
• Assume 100% dissociation – 1 mol of calcium chloride produces one mol of calcium ions and 2moles of chloride ions –
3 moles of ions total

• Write the equation for the dissociation of each of the following in water, and then determine the # of moles of each ion produced as well as the total number of moles of ions produced.
• A. 1 mol ammonium chloride
• B. 1 mol sodium sulfide
• C. 0.5 mol barium nitrate

A. Table 14-1 pg. 427 Solubility rules
B. Would the following be soluble? Which rule?
• (NH
4
)
2
S(s) → 2NH
4
+
• Cd(NO
3
)
2
(s) →
(aq) + S 2(aq)
C. When something is soluble it remains in solution(aq). If it is not soluble, it precipitates(s) out of solution.

• Reactions of ions in aqueous solutions
• Only includes compounds and ions that undergo a chemical change in a reaction in an aqueous solution.
1. Write overall equation
2. Write formula equation (Is each product soluble or not)
3. Write overall ionic equation -Dissociate soluble compounds into ions. Precipitates are shown as solids.
4. Cancel out spectator ions. Do not undergo any chemical change and do not take part in the reaction. Found in solution before and after reaction.
5. Write net ionic equation.

1. Will a precipitate form when solutions of ammonium sulfide and cadmium nitrate are combined? Write net ionic equation.
Step 1 (NH
4
)
2
S + Cd(NO
3
)
2
→
2 NH
4
NO
3
+ CdS
Step 2 (NH
4
)
2
S(aq) + Cd(NO
3
)
2
(aq) →
2 NH
4
NO
3
(aq) + CdS(s)
Ammonium nitrate is soluble – Rule #2
Cadmium sulfide is not soluble – precipitate –
Rule #6

Step #3 Cd 2+ (aq) +2NO
(aq) →CdS(s) + 2NO
3
-
3
-
(aq) + 2NH
(aq) + 2NH
4
+ (aq) + S 2-
4
+ (aq)
Step #4 Cd 2+ (aq) +2NO
3
(aq) + 2NH
4
+ (aq) + S 2-
(aq) →CdS(s) + 2NO
3
(aq) + 2NH
4
+ (aq)
Step #5 Cd 2+ (aq) + S 2(aq) →CdS(s)

Problem #2 Will a precipitate form when aqueous solutions of zinc nitrate and ammonium sulfide are combined?
1. Equation for double replacement
2. Formula equation (includes state of products)
3. Overall ionic equation
4. Net ionic equation – cancel out spectator ions.

3. Will a precipitate form if solutions of potassium sulfate and barium nitrate are combined? If so, write the net ionic equation for the reaction.
4. Will a precipitate form if solutions of potassium nitrate and magnesium sulfate are combined? If so, write the net ionic equation for the reaction.