Experiment 1D (Corrosion of Metal that Occurs on Copper and Iron):
Aim: To study the corrosion of copper and iron.
Problem statement: Do copper and iron undergo corrosion?
Hypothesis: Corrosion of copper metal produces blue precipitate and corrosion of iron metal produces brown precipitate.
Variables:
(a) Manipulated variable : Copper and iron.
(b) Responding variable : Presence of blue and brown precipitate.
(c) Fixed variable : Salt solution.
Materials: 20 cm of copper wire, 20 cm of iron wire, 0.5 mol dm−3 of sodium chloride, NaCl solution, 0.05 mol dm−3 of potassium chloride, KCl solution and 0.5 mol dm−3 of sodium hydroxide, NaOH solution.
Apparatus: Test tubes, test tube rack, sandpaper, beaker, tripod stand, wire gauze and Bunsen burner.
Procedure:
1. Clean the copper wire and iron wire using sandpaper.
2. Coil the copper wire and iron wire before putting them into two separate test tubes.
3. Add 12 cm3 of 0.5 mol dm−3 of sodium chloride, NaCl solution, 6 cm3 of 0.05 mol dm−3 of potassium chloride, KCl solution and 2 cm3 of 0.5 mol dm−3 of sodium hydroxide, NaOH solution into a beaker. Heat the mixture.
4. Pour the mixture into the test tubes until it covers the metals as shown in Figure 1.40.
5. Place both test tubes on the test tube rack and keep them aside for 3 days.
6. Record all observations.
Results:
Record your observations and inferences in a suitable table.
Discussion:
1. What is the purpose of using sodium hydroxide, NaOH in this experiment?
2. Based on the observations in this experiment, write the half equations for the reactions that occur.
3. What is the conclusion of this experiment?
Answer:
Result:
1. To detect the presence of Cu2+ ions and Fe2+ ions.
2.
Copper : Cu → Cu2+ + 2e−
Iron :
Fe → Fe2+ + 2e−
Fe2+ → Fe3+ + e−
3. Metal corrosion occurs when metal atom loses electrons to form metal ions.
Aim: To study the corrosion of copper and iron.
Problem statement: Do copper and iron undergo corrosion?
Hypothesis: Corrosion of copper metal produces blue precipitate and corrosion of iron metal produces brown precipitate.
Variables:
(a) Manipulated variable : Copper and iron.
(b) Responding variable : Presence of blue and brown precipitate.
(c) Fixed variable : Salt solution.
Materials: 20 cm of copper wire, 20 cm of iron wire, 0.5 mol dm−3 of sodium chloride, NaCl solution, 0.05 mol dm−3 of potassium chloride, KCl solution and 0.5 mol dm−3 of sodium hydroxide, NaOH solution.
Apparatus: Test tubes, test tube rack, sandpaper, beaker, tripod stand, wire gauze and Bunsen burner.
Procedure:
1. Clean the copper wire and iron wire using sandpaper.
2. Coil the copper wire and iron wire before putting them into two separate test tubes.
3. Add 12 cm3 of 0.5 mol dm−3 of sodium chloride, NaCl solution, 6 cm3 of 0.05 mol dm−3 of potassium chloride, KCl solution and 2 cm3 of 0.5 mol dm−3 of sodium hydroxide, NaOH solution into a beaker. Heat the mixture.
4. Pour the mixture into the test tubes until it covers the metals as shown in Figure 1.40.
5. Place both test tubes on the test tube rack and keep them aside for 3 days.
6. Record all observations.
Results:
Record your observations and inferences in a suitable table.
Discussion:
1. What is the purpose of using sodium hydroxide, NaOH in this experiment?
2. Based on the observations in this experiment, write the half equations for the reactions that occur.
3. What is the conclusion of this experiment?
Answer:
Result:
1. To detect the presence of Cu2+ ions and Fe2+ ions.
2.
Copper : Cu → Cu2+ + 2e−
Iron :
Fe → Fe2+ + 2e−
Fe2+ → Fe3+ + e−
3. Metal corrosion occurs when metal atom loses electrons to form metal ions.