Zadanie 1b
The second step converts nitrogen monoxide to nitrogen dioxide. 2 NO(g) + O2(g) ⇌ 2 NO2(g) ΔH⊖ = −114 kJ mol−1 (i) Identify the oxidation state of nitrogen in NO and in NO2. (ii) State the equilibrium constant…
Oxidation, reduction and redox agents
Define oxidation and reduction in terms of electron transfer, change in oxidation state and gain or loss of oxygen or hydrogen, and use oxidation states to identify the species oxidized and reduced and the oxidizing and reducing agents in a reaction.
Tę umiejętność sprawdzają 32 zadania wzorowane na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 32 Otwórz w wyszukiwarce z filtrami
Zadanie 23
Which statement about this reaction of permanganate ions with iron(II) ions is correct? MnO4−(aq) + 5 Fe2+(aq) + 8 H+(aq) → Mn2+(aq) + 5 Fe3+(aq) + 4 H2O(l) A. MnO4− is the reducing agent B. Fe3+ is reduced C. The oxidation state of…
Zadanie 24
Which statement about this reaction is correct? 2 Cl2 + O2 → 2 Cl2O A. Chlorine is the reducing agent. B. Oxygen is the reducing agent. C. Chlorine is reduced. D. Oxygen is oxidized.
Zadanie 29
What happens to hydrogen in the following reaction? Each option states whether hydrogen is oxidized or reduced and the change in its oxidation state. Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) A. Oxidized, from +1 to 0 B. Oxidized, from 0 to +1 C. Reduced,…
Zadanie 1c
A related nitrile, ethanenitrile, CH3CN, reacts with hydrogen according to the equilibrium: CH3CN(g) + 2 H2(g) ⇌ CH3CH2NH2(g) (i) Write the expression for the equilibrium constant, K, for this reaction. (ii) Determine the oxidation states that…
Zadanie 7b
Nitrogen dioxide reacts with rain water and oxygen to form nitric acid. (i) State an equation for this reaction, including state symbols. (ii) Explain, with reference to the oxidation states of two elements, why this is a redox reaction. (iii) Describe the…
Zadanie 29
Which change represents oxidation of the functional group? A. CH3COCH3 → CH3CH(OH)CH3 B. CH3CH(OH)CH3 → CH3COCH3 C. CH3CH2COOH → CH3CH2CHO D. CH3CH=CH2 → CH3CH2CH3
Zadanie 1c
Sulfur dioxide can also be removed from flue gas by reaction with hydrogen peroxide, forming sulfuric acid. SO2(g) + H2O2(aq) → H2SO4(aq) Deduce which element is reduced in this process, indicating the initial and final oxidation states.
- Tabela do uzupełnienia
Zadanie 26
Which row identifies the oxidizing agent and the reducing agent in the reaction below? 3 Cu(s) + 2 NO3−(aq) + 8 H+(aq) → 3 Cu2+(aq) + 2 NO(g) + 4 H2O(l) A. Oxidizing agent: Cu, reducing agent: NO3− B. Oxidizing agent: NO3−, reducing…
Zadanie 1a
Deduce the oxidation state of bromine in the reactant and in each of the two products. Reactant Br2: Product HOBr: Product HBr:
Zadanie 26
Calcium hydride is used as a portable source of hydrogen for fuel cells. It reacts with water as shown. CaH2(s) + 2 H2O(l) → Ca(OH)2(aq) + 2 H2(g) Which statement is correct? A. Calcium is reduced from +2 to 0. B. Hydrogen in CaH2 is oxidized from…
Zadanie 4a
(i) State the oxidation states of carbon in carbon monoxide and in carbonyl chloride. (ii) For each of CO and Cl2 in the forward reaction, state whether it acts as an oxidizing agent or a reducing agent, and whether it is oxidized or reduced.
Zadanie 6b
Potassium permanganate reacts with potassium iodide in alkaline solution. 6 MnO4−(aq) + I−(aq) + 6 OH−(aq) → 6 MnO42−(aq) + IO3−(aq) + 3 H2O(l) Identify the species oxidized and the number of electrons transferred in the equation as written.
Zadanie 22
Which statement is correct for the following spontaneous reaction? 2 I−(aq) + H2O2(aq) + 2 H+(aq) → I2(aq) + 2 H2O(l) A. I− is the oxidizing agent and H2O2 is oxidized B. I− is the oxidizing agent and H2O2 is reduced C.…
Zadanie 21
In which reaction does N2 act as a reducing agent? A. N2(g) + 3 H2(g) → 2 NH3(g) B. 3 Mg(s) + N2(g) → Mg3N2(s) C. N2(g) + O2(g) → 2 NO(g) D. 6 Li(s) + N2(g) → 2 Li3N(s)
Zadanie 23
Aqueous bromine, Br2(aq), is added separately to aqueous potassium chloride and to aqueous potassium iodide. Which statement is correct? A. Bromine reacts with both solutions, oxidizing the chloride ions and the iodide ions. B. Bromine reacts with the…
Zadanie 2a
All the species in the titration are almost colourless except MnO4−, which is intensely purple. The spinach extract, however, is coloured green by chlorophyll. (i) State the colour change at the end point. (ii) Outline how adding distilled water to the…
Zadanie 21
Which change involves the oxidation of chlorine? A. Cl2 → Cl− B. ClO4− → ClO3− C. Cl2 → ClO3− D. HCl → Cl−
Zadanie 21
Which element has more than one oxidation state in its compounds? A. Sodium B. Magnesium C. Fluorine D. Sulfur
Zadanie 23
Which species could be reduced to form elemental sulfur, S? A. H2S B. ZnS C. SO2 D. CS2
Zadanie 1b
Ultraviolet (UV) light is being investigated as a way of killing micro-organisms in juice without heating it, so that less vitamin C is lost. The absorption spectrum of a dilute aqueous solution of sorbic acid, a preservative that is added to some bottled…
- Materiał graficzny
Zadanie 1d
The vitamin C content of a juice can be found by titrating a sample against a standard iodine solution. Starch is used as the indicator: it forms a dark blue-black complex with the first excess of iodine once all the vitamin C has reacted.…
Zadanie 1b
UV-C irradiation is an alternative to heat treatment that causes less loss of nutrients. The absorption spectrum of a solution of vitamin C is shown. (i) Deduce the type of electromagnetic radiation absorbed by vitamin C. Use section 5 of the data booklet.…
- Materiał graficzny
Zadanie 1d
The concentration of vitamin C in juice can be measured by a redox titration. A sample of acidified juice containing excess iodide ions and starch solution is titrated with potassium iodate solution. Iodate ions react with iodide ions to produce iodine…
Zadanie 22
Zinc reacts with an aqueous solution of ethanoic acid. Zn(s) + 2 CH3COOH(aq) → Zn(CH3COO)2(aq) + H2(g) Which combination shows the role of the acid and the gas formed? A. oxidizing agent, H2(g) B. oxidizing agent, CO2(g) C. reducing agent,…
Zadanie 22
Magnesium ribbon is added to aqueous ethanoic acid. Which combination gives the role of the acid and a product formed from it? A. Oxidizing agent, H2(g) B. Oxidizing agent, CO2(g) C. Reducing agent, H2(g) D. Reducing agent, CO2(g)
Zadanie 1d
The presence of calcium nitride in the product can be demonstrated by adding water. The nitride is hydrolysed to form calcium hydroxide and ammonia. (i) Calculate coefficients that balance the equation for the reaction: __ Ca3N2(s) + __ H2O(l) →…
Zadanie 1c
Identify the oxidizing agent in the reaction of sodium with water and justify your answer in terms of oxidation states.
Zadanie 21
In which species would nitrogen be oxidized if it were converted to N2O? A. NO2 B. NH4+ C. HNO3 D. N2O3
Zadanie 21
Which species could be reduced to form SO2? A. S8 B. H2S C. SO32− D. SO42−
Zadanie 22
Which combination best describes what is happening to propene, CH3CH=CH2, in the equation below? CH3CH=CH2(g) + H2(g) → CH3CH2CH3(g) A. Oxidation and addition B. Oxidation and substitution C. Reduction and addition D. Reduction and substitution
Zadanie 22
Which species is the reducing agent in the reaction below? Cr2O72−(aq) + 14 H+(aq) + 6 Fe2+(aq) → 2 Cr3+(aq) + 6 Fe3+(aq) + 7 H2O(l) A. Cr2O72− B. H+ C. H2O D. Fe2+