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標題:
oxidation and reduction reactions
發問:
1.can copper (II) sulfate solution be stored in an iron container? explain your answer. 2. aqueous solution containing Fe2+ ions are unstable in air. explain why such solutions can be preserved by the presence of iron nails
最佳解答:
The above answerer has got some conceptual mistakes in the observation and reaction. 1. When copper (II) sulfate solution is stored in an iron container, there will occur a metal displacement reaction. It is due to, iron metal is more reactive than copper metal. i.e. Iron metal loses electrons more easily and to form iron (II) ions. Copper ions gained/accepted the lost electrons from iron metal to form copper. Chemical equation: CuSO4 (aq) + Fe (s)-> FeSO4 (aq) + Cu (s) Ionic equation: Cu2+ (aq) + Fe (s) -> Cu(s) + Fe2+ (aq) *Please notice that Fe3+ ions wouldn't form because iron atoms do not have a great enough energy to lose 3 electrons OR you may say, the oxidizing power of sulphate ions is not high enough to take away 3 electrons from each iron atom. From the Article copper in Wikipedia, "In an illustration of a 'single metal replacement reaction', iron is submerged in a solution of copper sulfate. Upon standing, iron dissolves and copper precipitates. Fe + CuSO4 → FeSO4 + Cu The copper can also be electroplated to the iron." The above answerer don't argue about which one is correct. Observation: 1. The solution turns from blue (or green) to pale green. 2. The inside of iron container is coated with a layer of brown (or reddish-brown) copper metal. THE IRON METAL WOULD NOT DISSOLVE. The iron metal is not placed in strong acid, it wouldn't get dissolved. = = It's just coated with a layer of copper metal... You may call that electroplating 電鍍... 2. Oxygen molecules in the air dissolves into water to form oxygen ions. The iron atoms in iron nails donate/lose electrons to oxygen ions. As I've written, when an atom tends to lose more electrons, it'll need a greater energy to lose electrons. More energy is required, i.e., the lower reactivity is. Therefore iron atoms is more reactive than iron(II) ions. Iron atoms oxidize instead of iron(II) ions.
i just know how to answer Q. 1. Sorry! i think u what u mean is copper(II) sulphate. Right? it cannot be stored in an iron container.As CuSO4 will react w/ iron and give iron(III) sulphate. 2CuSO4 + 3Fe -> Fe3(SO4)2 + 2Cu Observation: 1. Fe dissolve slowly 2. reddish brown solid(Cu) is formed 3. the solution turn from blue to green
oxidation and reduction reactions
發問:
1.can copper (II) sulfate solution be stored in an iron container? explain your answer. 2. aqueous solution containing Fe2+ ions are unstable in air. explain why such solutions can be preserved by the presence of iron nails
最佳解答:
The above answerer has got some conceptual mistakes in the observation and reaction. 1. When copper (II) sulfate solution is stored in an iron container, there will occur a metal displacement reaction. It is due to, iron metal is more reactive than copper metal. i.e. Iron metal loses electrons more easily and to form iron (II) ions. Copper ions gained/accepted the lost electrons from iron metal to form copper. Chemical equation: CuSO4 (aq) + Fe (s)-> FeSO4 (aq) + Cu (s) Ionic equation: Cu2+ (aq) + Fe (s) -> Cu(s) + Fe2+ (aq) *Please notice that Fe3+ ions wouldn't form because iron atoms do not have a great enough energy to lose 3 electrons OR you may say, the oxidizing power of sulphate ions is not high enough to take away 3 electrons from each iron atom. From the Article copper in Wikipedia, "In an illustration of a 'single metal replacement reaction', iron is submerged in a solution of copper sulfate. Upon standing, iron dissolves and copper precipitates. Fe + CuSO4 → FeSO4 + Cu The copper can also be electroplated to the iron." The above answerer don't argue about which one is correct. Observation: 1. The solution turns from blue (or green) to pale green. 2. The inside of iron container is coated with a layer of brown (or reddish-brown) copper metal. THE IRON METAL WOULD NOT DISSOLVE. The iron metal is not placed in strong acid, it wouldn't get dissolved. = = It's just coated with a layer of copper metal... You may call that electroplating 電鍍... 2. Oxygen molecules in the air dissolves into water to form oxygen ions. The iron atoms in iron nails donate/lose electrons to oxygen ions. As I've written, when an atom tends to lose more electrons, it'll need a greater energy to lose electrons. More energy is required, i.e., the lower reactivity is. Therefore iron atoms is more reactive than iron(II) ions. Iron atoms oxidize instead of iron(II) ions.
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其他解答:i just know how to answer Q. 1. Sorry! i think u what u mean is copper(II) sulphate. Right? it cannot be stored in an iron container.As CuSO4 will react w/ iron and give iron(III) sulphate. 2CuSO4 + 3Fe -> Fe3(SO4)2 + 2Cu Observation: 1. Fe dissolve slowly 2. reddish brown solid(Cu) is formed 3. the solution turn from blue to green
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