Zadanie 1c
The final step can be summarized as: 3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g) ΔH⊖ = −138 kJ mol−1 (i) Sketch an energy profile for the overall reaction, indicating ΔH⊖ and the activation energy. (ii) Describe the…
- Materiał graficzny
Energy profiles for exothermic and endothermic reactions
Sketch and interpret energy profile diagrams with reaction coordinate on the x axis and potential energy on the y axis, marking reactants, products, activation energy and ΔH, and link the relative stability of reactants and products to the sign of ΔH.
Tę umiejętność sprawdza 13 zadań wzorowanych na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 13 Otwórz w wyszukiwarce z filtrami
Zadanie 3c
Sodium reacts vigorously with water. (i) Write an equation, with state symbols, for the reaction of sodium with water. (ii) Describe one observation from the reaction in (i). (iii) Sketch, on the axes below, an energy profile for this reaction. Label the…
- Materiał graficzny
Zadanie 19
Which classification is correct for this reaction? 2 Mg(s) + CO2(g) → 2 MgO(s) + C(s), heat is released A. Endothermic; temperature decreases; reactants more stable B. Exothermic; temperature decreases; products more stable C. Exothermic; temperature…
Zadanie 19
Which of the following processes are exothermic? I. K(g) → K+(g) + e− II. H2O(g) → H2O(l) III. Ag+(g) + Cl−(g) → AgCl(s) A. I and II only B. I and III only C. II and III only D. I, II and III
Zadanie 19
The diagram shows the energy profile of a reaction. Which expression could give the enthalpy change, ΔH, of this reaction in kJ mol−1? A. +87 − 215 B. −215 + 87 C. +215 − 87 D. −215 − 87
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Zadanie 18
The energy profile below was recorded for a reaction. Which pair of statements is consistent with it? In each option the first statement compares the enthalpy of the products with that of the reactants and the second gives the sign of ΔH. A. products…
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Zadanie 20
Which row correctly describes an endothermic reaction? A. The temperature of the surroundings rises and the products are more stable than the reactants. B. The temperature of the surroundings falls and the products are more stable than the reactants. C. The…
Zadanie 20
The potential energy profile of a reaction is shown. Which reaction has this energy profile? A. Cl2(g) → 2 Cl(g) B. CaCO3(s) → CaO(s) + CO2(g) C. N2O4(g) → 2 NO2(g) D. 2 Mg(s) + O2(g) → 2 MgO(s)
- Materiał graficzny
Zadanie 20
A student mixes a solution of citric acid with solid sodium hydrogencarbonate in an insulated polystyrene cup fitted with a thermometer. The energy profile of the reaction is shown. Which combination is correct? A. the temperature of the solution rises;…
- Materiał graficzny
Zadanie 26
In the energy profile of a reaction shown below, P, Q and R are energies measured from the same baseline. Which expressions give the activation energy of the forward reaction, Ea, and the enthalpy change of the forward reaction, ΔH? A. Ea = Q;…
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Zadanie 2f
The reaction is usually carried out at a high temperature in the presence of a catalyst. (i) On the axes provided, sketch the energy profile of the reaction for the uncatalysed and for the catalysed pathway, and show ΔH and the activation energies.…
- Materiał graficzny
Zadanie 16
The diagram shows the enthalpy profile of an exothermic reaction. Arrows I, II and III show energy differences on the profile. Which expression gives ΔH for the forward reaction? A. II − I B. I − II C. I + II D. III − II
- Materiał graficzny
Zadanie 8f
Ethane reacts with iodine vapour. C2H6(g) + I2(g) → C2H5I(g) + HI(g) (i) Calculate the enthalpy change of the reaction, ΔH, using section 12 of the data booklet. (ii) Draw and label an enthalpy level diagram for this reaction on the axes below.
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