How fast? The rate of chemical change

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.

• Materiał graficzny

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.

• Materiał graficzny

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.…

• Materiał graficzny

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…

• Materiał graficzny

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, TZ3wzorowane7 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…

• Materiał graficzny

Chemia IBPaper 2, maj 2026, TZ1wzorowane5 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) Explain why increasing the temperature would increase…

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…

• Materiał graficzny

Chemia IBPaper 2, maj 2026, TZ2wzorowane2 pktotwartełatwe (szac.)

Zadanie 4d

Propene can be reduced to propane by hydrogen gas in the presence of a platinum catalyst at 50 °C. Outline how the catalyst increases the rate of this reaction.

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…