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…
Le Chatelier's principle
Apply Le Chatelier's principle to predict and explain how changing concentration, pressure (or volume) or temperature shifts the position of equilibrium, and how a catalyst shortens the time to reach equilibrium without changing the position or K.
Tę umiejętność sprawdza 30 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 30 Otwórz w wyszukiwarce z filtrami
Zadanie 2a
Iodine crystals, I2(s), were sealed in a flask and left until an equilibrium was reached with violet vapour above the crystals. I2(s) ⇌ I2(g) (i) Name the change of state from I2(s) to I2(g) and state the type of force between…
Zadanie 2b
The oxidation of sulfur dioxide to sulfur trioxide is an equilibrium reaction. 2 SO2(g) + O2(g) ⇌ 2 SO3(g) (i) State the equilibrium constant expression, K, for the reaction. (ii) Explain, with a reason, how compressing the gas mixture at constant…
- Materiał graficzny
Zadanie 23
Which change would shift the position of this equilibrium towards the products? H2(g) + I2(g) ⇌ 2 HI(g) ΔH = −9 kJ mol−1 A. Increase pressure B. Decrease pressure C. Increase temperature D. Decrease temperature
Zadanie 23
How does an increase in pressure, at constant temperature, affect the position of the following equilibrium and the value of the equilibrium constant, Kc? N2O4(g) ⇌ 2 NO2(g) A. Shifts to the left; Kc is unchanged B. Shifts to…
Zadanie 1e
The amount of NO2 prepared was checked by titration. The gas was first absorbed in water: 2 NO2(g) + H2O(l) → HNO3(aq) + HNO2(aq) The resulting solution was made up to 200.0 cm3 in a volumetric flask, and 20.0 cm3 portions…
- Tabela do uzupełnienia
Zadanie 2b
When potassium thiocyanate solution is added to a pale yellow solution containing iron(III) ions, the following equilibrium is established. [Fe(H2O)6]3+(aq) + SCN−(aq) ⇌ [Fe(SCN)(H2O)5]2+(aq) + H2O(l) [Fe(H2O)6]3+(aq) is pale yellow and…
- Materiał graficzny
Zadanie 3b
The volume of the reactor containing the equilibrium mixture described in 3a is suddenly increased at constant temperature. Sketch, on the axes below, how the concentration of hydrogen changes with time until the new equilibrium is established.
- Materiał graficzny
Zadanie 20
Iron(III) ions and thiocyanate ions form a deep red complex ion in aqueous solution. Fe3+(aq) + SCN−(aq) ⇌ [Fe(SCN)]2+(aq) Which of the following correctly predicts the effect of a change on this equilibrium? A. Adding iron(III) nitrate solution…
Zadanie 23
The container holding the equilibrium mixture below is compressed to half its volume while the temperature is kept constant. Which row gives the change in the amount of PCl5 and the effect on the equilibrium constant, K?…
Zadanie 24
A sealed, rigid container holds the following gas-phase reaction at equilibrium. N2(g) + O2(g) ⇌ 2 NO(g) ΔH⊖ = +180 kJ mol−1 Which pair of changes would move the equilibrium position furthest towards the products? A.…
Zadanie 3a
(i) Deduce the expression for the equilibrium constant, K, for this reaction. (ii) 0.500 mol each of propan-1-ol and ethanoic acid, together with a small amount of concentrated sulfuric acid, reacted at constant volume. At equilibrium,…
Zadanie 3c
(i) Sketch the Maxwell–Boltzmann distribution curve for 298 K on the same axes as the 800 K curve. (ii) On the graph, annotate the position corresponding to the activation energy, Ea. (iii) With reference to the graph, explain why a lower…
- Materiał graficzny
Zadanie 1b
When sodium hydroxide solution is added to the water, a larger amount of bromine reacts. Explain this observation.
Zadanie 1c
A student compiles data on the solubility of bromine in water at different temperatures from several websites and textbooks. (i) Identify one problem that arises when the values from these sources are compared with one another. (ii) Each solubility is then…
- Tabela do uzupełnienia
Zadanie 1f
Ammonia from sweat and skin-care products reacts with HOBr to form bromamines: NH2Br, NHBr2 and NBr3. (i) Deduce an equation for the reaction of ammonia with HOBr(aq) that produces dibromamine, NHBr2(aq). (ii) The graph shows how…
- Materiał graficzny
Zadanie 1g
Hot tubs are usually kept at 38–40 °C. Suggest two reasons why running a hot tub at a lower temperature would be better for the environment.
Zadanie 3b
Predict, with a reason, the effect of increasing the total pressure, at constant temperature, on the position of equilibrium.
Zadanie 3c
Hydrogen fluoride, HF, released by aluminium smelters, dissolves in water to form a weak acid. HF(aq) + H2O(l) ⇌ H3O+(aq) + F−(aq) (i) State the equilibrium constant expression, Kc, for this reaction. (ii) State, with a reason, the…
Zadanie 18
Which pair of changes will both shift the position of equilibrium to the left? CH4(g) + H2O(g) ⇌ CO(g) + 3 H2(g) ΔH = +206 kJ mol−1 A. Decrease the temperature and increase the pressure B. Increase the temperature and increase…
Zadanie 3d
Sulfuryl chloride, SO2Cl2, is made industrially from sulfur dioxide and chlorine in the presence of an activated carbon catalyst. SO2(g) + Cl2(g) ⇌ SO2Cl2(g) ΔH⊖ < 0 (i) Sketch a potential energy profile for the forward reaction,…
Zadanie 18
Ammonia dissolves in water as shown in the equation below. What will happen if the temperature of the solution is increased? NH3(g) + H2O(l) ⇌ NH4+(aq) + OH−(aq) ΔH⊖ = −31 kJ mol−1 A. The equilibrium shifts to the left…
Zadanie 18
A saturated solution of magnesium hydroxide contains undissolved solid. Which change will shift the position of the equilibrium to the right? Mg(OH)2(s) ⇌ Mg2+(aq) + 2 OH−(aq) A. Adding more solid Mg(OH)2 B. Adding dilute hydrochloric acid C.…
Zadanie 2d
Deduce, using your answer to 2c(i), how the value of Kc changes when the temperature of the equilibrium mixture is increased.
Zadanie 2d
Using your answer to part 2c(i), deduce how the value of Kc changes when the temperature is raised.
Zadanie 18
Which equilibrium would shift to the left when the pressure is increased at constant temperature? A. H2(g) + I2(g) ⇌ 2 HI(g) B. C(s) + CO2(g) ⇌ 2 CO(g) C. N2(g) + 3 H2(g) ⇌ 2 NH3(g) D. 2 NO2(g) ⇌ N2O4(g)
Zadanie 18
Which equilibrium shifts to the left when the pressure on the system is increased at constant temperature? A. CaCO3(s) ⇌ CaO(s) + CO2(g) B. H2(g) + I2(g) ⇌ 2 HI(g) C. N2(g) + 3 H2(g) ⇌ 2 NH3(g) D. 2 SO2(g) + O2(g) ⇌ 2 SO3(g)
Zadanie 2c
Methanol is manufactured from carbon monoxide and hydrogen. The reaction involves the equilibrium: CO(g) + 2 H2(g) ⇌ CH3OH(g) (i) Deduce the expression for the equilibrium constant, Kc, for this equation. (ii) Explain why an increase in pressure…
Zadanie 3b
(i) On the axes below, sketch Maxwell–Boltzmann energy distribution curves for the methanol molecules at two temperatures, T1 and T2, where T2 > T1. (ii) Explain the effect of increasing the temperature on the equilibrium yield of methanal.
- Materiał graficzny
Zadanie 4a
(i) Deduce the structural formula and the empirical formula of B. (ii) Explain, with reference to Le Châtelier’s principle, the effect on the yield of B of using dilute rather than concentrated sulfuric acid as the catalyst. (iii) Compound A has a lower molar…
- Materiał graficzny