1. NOTES #4: Predicting Products (double replacement & combustion)
WCHS Chemistry
NEED PERIODIC TABLE & ION SHEET

2. DOUBLE REPLACEMENT KCl NaNO3 KNO3 NaCl Step 1: Predict & name products
Swtich ions! Cations (+) go with anions (-)
Step 2: Write NEUTRAL formulas for reactants & products
*Be careful!!! Formulas must be neutral (don’t just pull over the same # ions)!
Step 3: BALANCE (if needed)
Potassium nitrate
Sodium chloride
Potassium chloride + sodium nitrate →
→ +
KCl
NaNO3
KNO3
NaCl

3. DOUBLE REPLACEMENT Na2SO4 NH4I NaI (NH4)2SO4
Step 1: Predict & name products
Step 2: Write NEUTRAL formulas for reactants & products
Step 3: BALANCE (if needed)
Sodium sulfate + ammonium iodide → →
Sodium iodide
Ammonium sulfate
Na2SO4
NH4I
NaI
(NH4)2SO4

4. COMBUSTION
Step 1: Write the hydrocarbon and add oxygen
Yields carbon dioxide (CO2) and water (H2O)
Step 2: BALANCE
Ex: The chemical formula for Ethane gas is C2H6. What is the full balanced equation for its combustion? →
7 oxygen
HINT: Balance C and H first! :) 2
C2H6
3.5 7 O2 4 2
CO2 6 3
H2O
THEN... DOUBLE EVERYTHING!!!!