Nun im Themenbereich Redox_en
Topic RedoxAll problems and solutions as
pdf here.Learning objectives resp. question areas:
- Ab Redox-01 : Oxidation numbers
- Ab Redox-10 : Definitions
- Ab Redox-20 : Redox table, electrode potential
- Ab Redox-30 : applying the Nernst equation
- Ab Redox-40 : Batteries - Car battery
- Ab Redox-50 : electrolysis
- This forum has 35 topics, 35 replies, and was last updated 4 days, 22 hours ago by .
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- Oxidation numbers (Redox-01)Determine the oxidation numbers of all atoms involved
- H2
- F2
- Na+
- S2-
- H2O
- Fe3O4
- CH4
- CH3F
- CHF3
- CH4O
- N2O4
- NO
- HNO3
- H3O+
- NH+4
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- 4 days, 22 hours ago
- Redox, definitions (Redox-10)Define the following concepts in relation to electron emission – electron absorption.
- Reduction
- Oxidation
- reducing agent
- oxidizing agent
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- 4 days, 22 hours ago
- Redox, definitions, oxidation numbers (Redox-11)Define the following concepts in relation to the oxidation numbers
- Reduction
- Oxidation
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- 4 days, 22 hours ago
- Redox, use of the definitions (Redox-12)Methane, CH4, is burned.
- Formulate the reaction equation
- Determine all oxidation numbers
- Apply the concepts reduction and oxidation
- Is O2 an oxidizing agent or reducing agent? Justify the choice.
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- 4 days, 22 hours ago
- Electrolysis – a redox reaction (Redox-13)Is the electrolysis of water a acid-base chemistry reaction or a redox-reaction? Why not?
Note: Electrolysis is the breakdown of water into its constituents by electricity:
2·H2O ⇄ 2·H2 + 1·O2 - 1
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- 4 days, 22 hours ago
- Redox, redox table, electrode potentials (Redox-14)Answer the following questions. Give each as proof of this also examples at.
- Are metals always a reducing agent?
- Are metallions always oxidizing agents?
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- 4 days, 22 hours ago
- Redox, reaction 3 (Redox-15)The following equation is given. If it is equal, determine all the oxidation numbers, where does the oxidation occur, where does the reduction occur?
Ag + HNO3 ⇄ AgNO3 + NO2 + H2O - 1
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- 4 days, 22 hours ago
- Redox, reaction 4 (Redox-16)The following, already balanced reaction equation is given. Determine all oxidation numbers. Where does the oxidation take place, where is the reduction?
3SO3^2- + Cr2O7^2- + 8H^+ -> 2Cr^3+ + 3SO4^2- + 4H2O - 1
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- 4 days, 22 hours ago
- Redox, reaction 5 (Redox-17)Subsequent, already balanced reaction equations are given. Determine all oxidation numbers. Where does the oxidation take place, where does the reduction take place? If the oxidation number does not change, indicate this as well.
{a: } 3SO3^2- + Cr2O7^2- + 8H^+ -> 2Cr^3+ + 3SO4^2- + 4H2O{b: } N2H4 + 4Fe(CN)6^3- + 4OH^- -> N2 + 4Fe(CN)6^4- + 4H2O{c: } Ru + 6Cl^- + 3NO3^- + 6H^+ -> RuCl6^3- + 3NO2 + 3H2O{d: } ClO3^- + 3SO2 + 3H2O -> 3SO4^2- + Cl^- + 6H^+{e: } 3H2S + 2HNO3 -> 2NO + 3S + 4H2O{f: } KSCN + 4H2O + 4I2 -> KHSO4 + 7HI + ICN - 1
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- 4 days, 22 hours ago
- Redox, reaction 6 (Redox-18)The following, already balanced reaction equation is given. Determine all oxidation numbers. Where does the oxidation take place, where is the reduction?
What ‘s so special about this place ?Cl2 + 2NaOH -> NaCl + NaClO + H2O - 1
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- 4 days, 22 hours ago
- Redox, multiple choice (Redox-20)Answer the following questions with yes or no. Yes means that the whole question (i.e. any subsequent paragraphs) is correct.
The following table is based on:
Li → Li+ E= -3.05 V
K → K+ E = -2.93 V
…
2·F– → F2 E = +2.87 V- Reducing agents are in the redox table on the left.
- Oxidizing agent standing in the redux table on the right.
- The higher up the redox table an oxidizing agent (right) is, the stronger it is.
- In an oxidation, electrons are emitted from the oxidizing agent.
- All metals can rust.
- A substance oxidizes when it…
It emits protons.
It's picking up protons.
It emits electrons.
It's picking up electrons. - Oxidation always takes place at the anode.
- A strong oxidizing agent has a low tendency to absorb electrons.
- A strong oxidizing agent has a high tendency to reduce itself.
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- 4 days, 22 hours ago
- Redox, reaction 1 (Redox-21)Tin (Sn) is added to an acidic solution. Note the reaction equation, oxidation and reduction. Is the acid here an oxidizing agent ?
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- 4 days, 22 hours ago
- Redox, reaction 2 (Redox-22)A pieces silver (Ag) is in a 1 mol/Liter NaOH given. Note the reaction equation, oxidation and reduction.
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- 4 days, 22 hours ago
- Redox, redux table, Herleitung-1 (Redox-23)The equation for the anode space (pH=14) for electrolysis is:
4·OH– → O2 + 2·H2O
Describe the same situation (including the electrons) for total for 6·H2O ! - 1
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- 4 days, 22 hours ago
- Redox, redux table, Herleitung-2 (Redox-24)In the cathode space (pH=0) the reaction equation is
2·H3O+ + 2·e– → H2 + 2·H2O
Forms such that they appear on the right-hand side 4·OH–. - 1
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- 4 days, 22 hours ago
- Redox, redux table, Herleitung-3 (Redox-25)In the cathode space (pH=0) the reaction equation is
4·H2O + 4·e– → 2·H2 + 4·OH–
and in the anode space (pH=14)
6·H2O → O2 + 4·H3O+ + 4·e–
Simplify as much as possible ! - 1
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- 4 days, 22 hours ago
- Redox, redux table, Herleitung-4 (Redox-26)Alternative derivation of the previous equation.
a) H2 + 2·H2O → 2·H3O+ (pH=7, -0.42 V)
b) 4·OH– → O2 + 2·H2O (pH=7, 0.83V)
The reaction would be mountaintop or lower left to upper right. the whole reaction with the indication that the reaction ·2 should be made.
The second question … [translation unavailable] ·2 - 1
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- 4 days, 22 hours ago
- Iron bromide (Redox-27)After a test, a solution of zinc sulfate is contaminated with copper ions. How can the copper ions be removed efficiently? Why does a distillation and filtration not work?
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- 4 days, 22 hours ago
- Redox, redux table, exercise 2 (Redox-29)Use the redox table to assess whether the following reactions are possible.
- Ag in copper sulphate
- Silver nitrate in copper
- You react (elementary) bromine with iron. Bromine is in excess.
- [translation unavailable] in 1 M HCl
- How can silver be extracted from nitrate in solid form? Only acids or bases are permitted as auxiliaries.
- Gold is to be dissolved in a solution. Please specify a suitable variant.
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- 4 days, 22 hours ago
- Redox, Redox table, Nernst 1 (Redox-30)
- What 's the Nernst equation ?
- What is the Nernst equation for diluted solutions of the same metal
- A concentrated Cu2+ – solution and a diluted Cu2+ – solution are given, each containing a Cu electrode. Solutions, only separated by a diaphragm, connected to each other? Use of which: other the concept reduction, oxidation, court of Justice at the catheter or [translation unavailable].
- How do you calculate the voltage between two different half-cells ?
- Calculate the potential of a silver cell with a concentration of 0.1 mol/l
- Calculate the potential of a silver cell with a concentration of 0.01 mol/l
- What is the voltage between two half-cells with a voltage of 0.1 and 0.01 mol/L?
- A zinc half cell is diluted by a factor of 1000. Calculate the voltage drop and the new potential.
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- 4 days, 22 hours ago
- Redox, Redox table, Nernst 2 (Redox-31)Calculate the potential for the following given solutions or reactions.
E = Eo + 0.059/n · log(ca(Oxidierte Form)/ cb(Reduzierte Form))- Zn → Zn2+, c(Zn2+) = 0.1 mol/L
- 2 Cl– → Cl2, c(Cl–) = 2 mol/L
- Mn2+ + 12 H2O → MnO–4 + 8 H3O+ , c(Mn2+) = x, c(MnO–4) = y
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- 4 days, 22 hours ago
- Redox, Redox table, Nernst 3 (Redox-32)What voltage is calculated for the Daniell element if at 298 K the concentration of the zinc sulphate solution is 0.001 mol/L and that of the copper sulphate solution is 0.8 mol/L.
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- 4 days, 22 hours ago
- Redox, Redox table, Nernst 4 (Redox-33)(a) What voltage is calculated for the Daniell element if at 298 K the concentration of the zinc sulphate solution and that of the copper sulphate solution is 1 mol/L each. Please specify the generally applicable equation for this.
(b) Calculate the new voltages assuming that after every 15 minutes the concentrations will decrease by 0.1 mol/L We have changed. - 1
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- 4 days, 22 hours ago
- Redox, car battery (Redox-40)In the case of an automotive battery, explain the following processes:
- Unloading
- Shopping
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- 4 days, 22 hours ago
- Redox, amp hours, Ah (Redox-41)In the case of a car battery, the following is added: 100 Ah, 12 V
So how many electrons (in mol) can flow in 5 hours? - 1
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- 4 days, 22 hours ago
- Redox, car battery, sales (Redox-42)A car batteries be full loaded and containing 1.5 litres a 30% mixtures of sulphuric acid. '[translation unavailable]' be the concentration only still 20%. How much lead or lead oxide was applied each time?
Note: the density the 30% sulphuric acid-solution of which:1.84 g/cm3 . The density is equal to the discharge. - 1
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- 4 days, 22 hours ago
- Electrolysis – a redox reaction, cloze exercise (Redox-50)Complete the following gaps with meaningful content. The reaction under consideration is the electrolysis of water.
… charged oxonium ions … … travel in the electric field to the … charged electrode (cathode), where they each receive an electron … Hydrogen atoms are formed, which combine with another H atom created by… to form a hydrogen molecule. What's left are water molecules.
The isolated gaseous hydrogen rises at the cathode, where the cathode space becomes … the negatively charged hydroxide anions migrate to the … anode, where hydroxidions with protons (H+ and H3O+) neutralize to water or convert to oxygen at the anode under …
Here, too, the isolated oxygen rises as a gas at the anode, at the same time the anode space becomes…. The protons created travel in the direction of… – analogous to the processes in the cathode space. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 1 (Redox-51)Copper is obtained electrolytically from Cu2+ – ions. In a electrolytic cells is a Cu2+ -withdrawn solution
30 min with a power intensity ofI = 2.5 A electrolytic. Calculate the separated mass m(Cu) at an electrolysis efficiency of 92.5%.
Note 1: m/M = I·t/(z·F)
Note 2: Assume 100% efficacy in a first step.
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 2 (Redox-52)A silver nitrate solution is electrolyzed at a current strength of 2.54 A. The mass of silver is released in 45 minutes. The efficiency is 90%.
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 3 (Redox-53)15 m2 a metal surface area should with a 35 µm thick chromic layer coated are. Chromes has a density of
7.15 g/cm3 .
(a) Calculate the mass of chromium to be excreted.
(b) Separation shall be made from an CrO3 – solution. How long to be electrolyzed if the current strength is 450 A And the effectiveness is 90%.
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 4 (Redox-54)How long must a electricity the strength 0.45 A flow, so that from a CuCl2 solution 3.5 g copper discharged are?
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 5 (Redox-55)How long does a current of 10 A have to flow (about the usual 'household current ') before electrons of a total mass of 1 kg are passed through the conductor cross-section?
Notes m(e–) = 9.1·10-31 kg, load 1e– = 1.602·10-19 C
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 6 (Redox-56)A shell with a surface of 120 cm2 should through electrolysis a silver nitrate solution a 0.2 mm thick silver transhipment received. Calculate the time required if the current strength is 10 A. The density of the silver is
10.5 g/cm3 .
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 7 (Redox-57)Calculate the thickness of the copper layer that a current of 5.8 A dissolves evenly in 3 hours on a sphere with a radius of 8.3 cm.
Note 1: The surface of a sphere is 4·pi·r2
Note 2: Coppering was carried out with a copper sulphate solution
Note 3: Dichte(Cu) = 8.9 g/cm3
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
- Redox, electrolysis, 8 (Redox-58)800 mg of copper at I=180mA should be removed from a copper sulphate solution at the cathode. Calculate (a) the time duration of electrolysis and (b) determines the volume of oxygen that is created simultaneously under normal conditions (298 K, 101300 N/m2).
The general gas equation is p·V=n·R·T, whereasR = 8.314 J/molK .
Note : identical exercise also at the same time, subjects salts. - 1
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- 4 days, 22 hours ago
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