Rate of reaction sim

What the sim shows

0.024 g of magnesium ribbon (0.99 mmol, Ar 24.3) reacts with 50 cm³ of 1.0 mol/dm³ hydrochloric acid: Mg + 2HCl → MgCl₂ + H₂. The acid is a large excess (50 mmol against 2.0 mmol needed), so its concentration barely changes, and every run gives the same amount of hydrogen (23.7 cm³ at RTP, 24.0 dm³/mol) at any temperature; only the speed changes. Gas volumes are read at RTP. Hotter particles have more kinetic energy and move faster, so they collide more often and more of the collisions have at least the activation energy. The gas collected follows a simplified first-order model, V = V<sub>final</sub>(1 − e<sup>−kt</sup>), with k from the Arrhenius equation (Ea = 50 kJ/mol, k = 0.020 s⁻¹ at 20 °C, 0.235 s⁻¹ at 60 °C), so a 10 °C rise about doubles the rate near room temperature. Half the gas comes off in 35 s at 20 °C and 3.0 s at 60 °C. Ea and k are illustrative values, not measured for this reaction, and real curves are not exactly first order. Time runs 10× fast (1 s on screen = 10 s of reaction) and each run stops at 99%. The model ignores the heat the reaction gives out and gas lost or dissolved.

• Plunger: slides out as hydrogen collects
• Water bath sets the temperature
• Stopwatch: reaction time

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