How fast? The rate of chemical change

Chemia IBPaper 2, maj 2026, TZ1wzorowane4 pktotwarteśrednie (szac.)

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

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

Zadanie 1f

Explain how the rate at which the light intensity was falling after 15 minutes in the 44.8 °C run could be determined from the graph.

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Chemia IBPaper 1B, maj 2026, TZ2wzorowane3 pktotwarteśrednie (szac.)

Zadanie 1g

The graph shows the maximum rate of decrease in light intensity for each run, plotted against temperature. (i) Draw the best-fit curve on the graph. (ii) Suggest two possible conclusions that can be drawn from the investigation.

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Chemia IBPaper 1B, maj 2026, TZ3wzorowane5 pktotwarteśrednie (szac.)

Zadanie 1a

(i) Write a balanced equation for the reaction, including state symbols. (ii) Deduce what property of this reaction makes it possible to follow its rate by both methods. (iii) Magnesium carbonate was used in excess so that all of the acid would react.…

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Chemia IBPaper 1B, maj 2026, TZ3wzorowane2 pktobliczenioweśrednie (szac.)

Zadanie 1b

In Method 1 the flask containing 25.0 cm³ of the aqueous acid was put on the balance, which was then set to zero; 0.400 g of MgCO₃ was added and the reading was noted every 20 seconds until the reaction had stopped. Each point is the mean of…

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Chemia IBPaper 2, maj 2026, TZ2wzorowane3 pktotwartełatwe (szac.)

Zadanie 2b

An ‘iodine clock’ experiment can be based on two reactions that occur at the same time. S₂O₈²⁻(aq) + 2 I⁻(aq) → 2 SO₄²⁻(aq) + I₂(aq) slow 2 S₂O₃²⁻(aq) + I₂(aq) → S₄O₆²⁻(aq) + 2 I⁻(aq) fast The iodine formed in the slow reaction is removed at…

Chemia IBPaper 2, maj 2026, TZ3wzorowane9 pktotwarteśrednie (szac.)

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…

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Chemia IBPaper 2, maj 2026, TZ3wzorowane4 pktobliczenioweśrednie (szac.)

Zadanie 2c

Nitrogen monoxide reacts with chlorine in the atmosphere: 2 NO(g) + Cl₂(g) → 2 NOCl(g) The rate equation was determined experimentally as Rate = k[NO]²[Cl₂]. (i) A student proposed the following mechanism and suggested that Step 1 was the…

• Tabela do uzupełnienia

Chemia IBPaper 2, maj 2026, TZ1wzorowane11 pktotwarteśrednie (szac.)

Zadanie 3c

Pentan-2-ol can form by reacting pent-1-ene with water in the presence of an acid catalyst. CH₂=CHCH₂CH₂CH₃(g) + H₂O(l) → CH₃CH(OH)CH₂CH₂CH₃(aq) ΔH^⊖ = −84 kJ mol⁻¹ (i) The first step of the mechanism for the formation of…

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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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