Measuring enthalpy changes

Chemia IBPaper 1B, maj 2026, TZ2wzorowane2 pktobliczenioweśrednie (szac.)

Zadanie 2c

Calculate the specific energy of ethanol for trial 5, in J g⁻¹. Use sections 1 and 2 of the data booklet. $\text{specific energy} = \dfrac{Q}{m_{\mathrm{fuel}}}$ m_water = 120.0 g

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Chemia IBPaper 1B, maj 2026, TZ2wzorowane2 pktotwartełatwe (szac.)

Zadanie 2f

Suggest two ways in which the error in this experiment could be reduced.

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Chemia IBPaper 2, maj 2026, TZ2wzorowane5 pktotwarteśrednie (szac.)

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…

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Chemia IBPaper 1A, maj 2026, TZ1wzorowane1 pktzamkniętełatwe (szac.)

Zadanie 15

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…

Chemia IBPaper 1A, maj 2026, TZ2wzorowane1 pktzamkniętełatwe (szac.)

Zadanie 15

Manganese(IV) oxide is added to a solution of hydrogen peroxide, which then decomposes much faster. Which quantity on the energy profile of the decomposition is the same with and without the catalyst? A. The activation energy of the forward reaction B. The…

Chemia IBPaper 1A, maj 2026, TZ3wzorowane1 pktzamknięteśrednie (szac.)

Zadanie 15

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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Chemia IBPaper 1A, maj 2026, TZ2wzorowane1 pktzamknięteśrednie (szac.)

Zadanie 16

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

Chemia IBPaper 1A, maj 2026, TZ2wzorowane1 pktzamkniętełatwe (szac.)

Zadanie 21

Which statements describe the activation energy of a reaction? I. The minimum energy that colliding particles must have in order to react II. The energy difference between the reactants and the transition state on an energy profile III. The energy difference…

Chemia IBPaper 1B, maj 2025, TZ3wzorowane4 pktotwarteśrednie (szac.)

Zadanie 1b

The sealed vessel was left for the reaction to proceed. Suggest two properties of the system, other than its colour, that could be measured to follow the progress of the reaction over time, and predict how each would change as the forward reaction proceeds.

Chemia IBPaper 2, maj 2025, TZ2wzorowane7 pktobliczenioweśrednie (szac.)

Zadanie 3a

Suppose carbonyl dibromide were made by a free-radical chain reaction of carbon monoxide, CO, with bromine vapour, Br₂, started by ultraviolet light. The questions below treat this hypothetical route with the bond-enthalpy model. (i) Write an…

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