Starter: Ionic Equations
1) 2Al + 6HNO3 🡪 2Al(NO3)3 + 3H2
2) Sr + H2SO4 🡪 SrSO4 + H2
Challenge:
3) NaCl(aq) +AgNO3(aq) →NaNO3(aq) + AgCl(s)
4) 2NaCl(aq) + CuSO4(aq) 🡪 Na2SO4 (aq) + CuCl2 (s)
CHALLENGE HINT:
Only aqueous ionic compounds can be broken down into their ions. Solids (precipitates) do not break down into ions and have a neutral charge.
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
1) 2Al (s) + 6HNO3 🡪 2Al(NO3)3 + 3H2
2Al + 6H+ + 6NO3- 🡪 2Al3+ + 6NO3- + 3H2
2Al + 6H+ 🡪 2Al3+ + 3H2
Al loses 3 electrons
H gains 1 electron
Oxidation
Reduction
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
2) Sr + H2SO4 🡪 SrSO4 + H2
Sr + 2H+ + SO42- 🡪 Sr2+ + SO42- + H2
Sr + 2H+ 🡪 Sr2+ + H2
Sr loses 2 electrons
H gains 1 electron
Oxidation
Reduction
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
3) NaCl(aq) +AgNO3(aq) →NaNO3(aq) + AgCl(s)
Na+ + Cl- + Ag+ + NO3- 🡪 Na+ + NO3- + AgCl
Cl- + Ag+ 🡪 AgCl
Cl- loses 1 electron
Ag gains 1 electron
Oxidation
Reduction
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
4) 2NaCl(aq) + CuSO4(aq) 🡪 Na2SO4 (aq) + CuCl2 (s)
2Na+ + 2Cl- + Cu2+ + SO42- 🡪 2Na+ + SO42- + CuCl2
2Cl- + Cu2+ 🡪 CuCl2
Cl loses 1 electron
Cu gains 2 electrons
Oxidation
Reduction
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Electrolysis - Recap
+
+
-
P
A
N
I
C
OSITIVE
NODE
EGATIVE
S
ATHODE
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Molten Ionic Compounds
A molten compound has been melted.
This means the ions are free to move.
E.g.
Molten Lead bromide
Pb2+
Pb2+
Pb2+
Pb2+
Br-
Br-
Br-
Br-
Br-
Br-
Br-
Br-
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Molten Ionic Compounds
E.g.
Molten Cobalt (II) chloride
Co2+
Cl-
Co2+
Co2+
Co2+
Cl-
Cl-
Cl-
Cl-
Cl-
Cl-
Anode – Chlorine gas
Cathode –
Cobalt solid
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Learning Check – Molten Ionic Compounds
Each of the molten compounds below are electrolysed.
State what ions are present in each compound.
Describe what would be given off at the anode and cathode.
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Compound | Ions | Anode | Cathode | |
Magnesium oxide | | | | |
Zinc (II) fluoride | | | | |
Silver chloride | | | | |
Iron (III) oxide | | | | |
Potassium bromide | | | | |
Sodium chloride | | | | |
Potassium selenide | | | | |
Magnesium telluride | | | | |
Lithium nitride | | | | |
Beryllium phosphide | | | | |
Mg2+ | O2- |
Zn2+ | F- |
Ag+ | Cl- |
Fe3+ | O2- |
K+ | Br- |
Na+ | Cl- |
K+ | Se2- |
Mg2+ | Te2- |
Li+ | N3- |
Be2+ | P3- |
Oxygen (gas) | Magnesium (solid) |
Fluorine (gas) | Zinc (solid) |
Chlorine (gas) | Silver (solid) |
Oxygen (gas) | Iron (solid) |
Bromine (gas) | Potassium (solid) |
Chlorine (gas) | Sodium (solid) |
Selenium (solid) | Potassium (solid) |
Tellurium (solid) | Magnesium (solid) |
Nitrogen (gas) | Lithium (solid) |
Phosphorus (solid) | Beryllium (solid) |
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Aqueous Compounds
An aqueous solution is found where a ionic compound has been dissolved in water.
The ions are free to move BUT there are more ions to consider.
Water molecules ionise to form hydrogen ions and hydroxide ions.
H2O H+ + OH-
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Co2+
Cl-
H+
OH-
Co2+
Co2+
OH-
OH-
Cl-
Cl-
H+
H+
H+
Positive Ions –
Co2+
H+
Negative Ions –
Cl-
OH-
Rule 1
The more reactive ion will remain in the solution, the less reactive ion will move.
Rule 2
If a halide ion is present in solution, the halogen will be produced at the anode.
What is the pH of the remaining solution?
E.g.
Aqueous Cobalt (II) chloride
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
E.g.
Aqueous Copper sulphate
Cu2+
OH-
SO42-
H+
H+
H+
H+
Cu2+
Cu2+
Cu2+
OH-
OH-
SO42-
SO42-
OH-
Positive Ions –
Cu2+
H+
Negative Ions –
SO42-
OH-
Describe what will be seen at the anode and the cathode.
Copper (Solid) at the Cathode
Oxygen (gas) at the Anode
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Learning Check – Aqueous Ionic Compounds
State what ions are present in each compound.
Describe what would be given off at the anode and cathode.
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Compound | Ions | Anode | Cathode | |
Copper chloride | | | | |
Sodium chloride | | | | |
Silver bromide | | | | |
Iron (II) sulphate | | | | |
Manganese (II) nitrate | | | | |
Barium fluoride | | | | |
Copper carbonate | | | | |
Chromium (III) sulphate | | | | |
Silver fluoride | | | | |
Magnesium carbonate | | | | |
Cu2+ H+ | Cl- OH- |
Na+ H+ | Cl- OH- |
Ag+ H+ | Br- OH- |
Fe2+ H+ | SO42- OH- |
Mn2+ H+ | NO3- OH- |
Ba2+ H+ | F- OH- |
Cu2+ H+ | CO32- OH- |
Cr3+ H+ | SO42- OH- |
Ag+ H+ | F- OH- |
Mg2+ H+ | CO32- OH |
Chlorine (gas) | Copper (solid) |
Chlorine (gas) | Hydrogen (gas) |
Bromine (gas) | Hydrogen (gas) |
Oxygen (gas) | Hydrogen (gas) |
Oxygen (gas) | Hydrogen (gas) |
Fluorine (gas) | Hydrogen (gas) |
Oxygen (gas) | Copper (solid) |
Oxygen (gas) | Hydrogen (gas) |
Fluorine (gas) | Silver (solid) |
Oxygen (gas) | Hydrogen (gas) |
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.
Exam Questions
Complete the exam question on Electrolysis.
Choose the difficulty of questions that you need to start with.
Starter | Activity 1 | Learning Check | Activity 2 | Learning Check | Activity 3 | Learning Check | Activity 4 | Learning Check |
Electrolysis
Wednesday, 11 December 2019
Grade 8 Explain why different gases are released at the electrodes in aqueous solutions. |
Grade 8 Explain why electrolysis can only occur when an ionic compound is molten or aqueous. |
Grade 6 Describe electrolysis in terms of movement of ions. |
HOT Question:
Explain why different molecules are released from the anode and cathode depending on the solution.