Module 11i Part W: Re-write Equations Ionically – Non REDOX Answers

The following Rules are written at the top of the Part G test:

Show as ions: soluble salts (aq) and strong acids (aq); leave as molecules/formula units insoluble salts (s), weak acids (aq), covalent molecules. (Strong hydroxide bases are hydroxides which are also soluble salts are written ionically.)

Strong Acids are: Perchloric Acid; Hydrochloric Acid; Nitric Acid; Sulfuric Acid; Hydrobromic Acid; Hydroiodic Acid.

Strong Bases are: Sodium hydroxide, Potassium hydroxide, Calcium hydroxide, Barium hydroxide, Strontium hydroxide

Here are a set of worked examples:

1. KOH (aq) + HNO₃(aq) à KNO₃(aq) + HOH(l)

Decide which compounds should be split into ions:

K|OH (aq) + H|NO₃(aq) à K|NO₃(aq) + HOH(l)

Strong base strong acid soluble salt covalent molecule

Rewrite the ionic species as ions, and leave the rest as compound formulas:

K¹⁺(aq)+OH^1-(aq)+H¹⁺(aq)+NO₃^1-(aq)àK¹⁺(aq)+NO₃^1-(aq)+HOH(l)

Cancel the Spectator Ions:

K¹⁺(aq)+OH^1-(aq)+H¹⁺(aq)+NO₃^1-(aq)àK¹⁺(aq)+NO₃^1-(aq)+HOH(l)

Final Net Ionic Answer:
1. KOH (aq) + HNO₃(aq) à KNO₃(aq) + HOH(l)

OH ^1-(aq) + H ¹⁺⁽aq) à HOH (l)

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2. CuSO₄ (aq) + Na₂CO₃ (aq) à CuCO₃ (s) + Na₂SO₄ (aq)

Decide which compounds should be split into ions:

Cu|SO₄ (aq) + Na₂|CO₃ (aq) à CuCO₃ (s) + Na₂|SO₄ (aq)

Soluble Salt Soluble Salt Insoluble salt Soluble Salt

Rewrite the ionic species as ions, and leave the rest as compound formulas

Cu²⁺⁽aq)+SO₄^2-(aq)+2Na¹⁺(aq)+CO₃^2-(aq)à

CuCO₃(s) + 2Na¹⁺⁽aq)+SO₄^2-(aq)

Cancel the Spectator Ions:

Cu²⁺⁽aq)+SO₄^2-(aq)+2Na¹⁺(aq)+CO₃^2-(aq)à

CuCO₃(s) + 2Na¹⁺⁽aq)+SO₄^2-(aq)

Final Net Ionic Answer:
2. CuSO₄ (aq) + Na₂CO₃ (aq) à CuCO₃ (s) + Na₂SO₄ (aq)

Cu ²⁺ + CO₃ ^2- à CuCO₃ (s)

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3. NaOH (aq) + NH₄NO₃ (aq) à NaNO₃ (aq) + NH₃ (g) + HOH (l)

Decide which compounds should be split into ions:

Na|OH (aq) + NH₄|NO₃ (aq) à Na|NO₃ (aq) + NH₃ (g) + HOH (l)

Strong Base Soluble Salt Soluble Salt molecular molecular

Rewrite the ionic species as ions, and leave the rest as compound formulas:

Na¹⁺⁽aq)+OH^1-(aq)+NH₄¹⁺(aq)+NO₃^1-(aq)à

Na¹⁺⁽aq)+NO₃^1-(aq) + NH₃ (g)+HOH(l)

Cancel the Spectator Ions:

Na¹⁺⁽aq)+OH^1-(aq)+NH₄¹⁺(aq)+NO₃^1-(aq)à

Na¹⁺⁽aq)+NO₃^1-(aq) + NH₃ (g)+HOH(l)

Final Net Ionic Answer:
3. NaOH (aq) + NH₄NO₃ (aq) à NaNO₃ (aq) + NH₃ (g) + HOH (l)

OH ^1- + NH₄ ¹⁺ à NH₃ (g) + H₂O (l)

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4. BaBr₂ (aq) + ZnSO₄ (aq) à BaSO₄ (s) + ZnBr₂ (aq)

Decide which compounds should be split into ions:

Ba|Br₂ (aq) + Zn|SO₄ (aq) à BaSO₄ (s) + Zn|Br₂ (aq)

Soluble Salt Soluble Salt Insoluble salt Soluble Salt

Rewrite the ionic species as ions, and leave the rest as compound formulas

Ba²⁺⁽aq)+ 2Br^1-(aq) + Zn²⁺(aq) + SO₄^2-(aq)à

BaSO₄(s) + Zn²⁺aq) + 2Br^1-(aq)

Cancel the Spectator Ions:

Ba²⁺⁽aq) + 2Br^1-(aq) + Zn²⁺(aq) + SO₄^2-(aq)à

BaSO₄(s) + Zn²⁺⁽aq) + 2Br^1-(aq)

Final Net Ionic Answer:
4. BaBr₂ (aq) + ZnSO₄ (aq) à BaSO₄ (s) + ZnBr₂ (aq)

Ba ²⁺ + SO₄ ^2- à BaSO₄ (s)

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5. Cr(OH)₂ (s) + HCl (aq) à First Complete the Product:

Cr(OH)₂ (s) + 2HCl (aq) à CrCl₂ (aq) + HOH (l)

Decide which compounds should be split into ions:

Cr(OH)₂ (s) + 2 H|Cl (aq) à Cr|Cl₂ (aq) + HOH (l)

Insoluble Salt Strong Acid Soluble Salt Molecular

Rewrite the ionic species as ions, and leave the rest as compound formulas:

Cr(OH)₂ (s) +2H¹⁺(aq) + 2Cl^1-(aq)àCr²⁺(aq)+ 2Cl^1-(aq) + HOH(l)

Cancel the Spectator Ions:

Cr(OH)₂ (s)+ 2H¹⁺(aq)+ 2Cl^1-(aq)à Cr²⁺(aq)+ 2Cl^1-(aq) + HOH(l)

Final Net Ionic Answer:
5. Cr(OH)₂ (s) + 2 HCl (aq) à CrCl₂ (aq) + H₂O (l)

Cr(OH)₂ (s) + 2 H ¹⁺ (aq) à Cr ²⁺ (aq) + 2 H₂O (l)

From the Textbook:

Video:

http://www.brightstorm.com/science/chemistry/chemical-reactions/net-ionic-equation/