Question

8a(ii - continued) Draw the energy profile diagram for the reaction H2(g)+I2(g)→2HI(g); ΔH=-13kJmol⁻¹. If the concentration of HI(g) increases from 0.000 to 0.002 moldm⁻³ in 80 seconds, what is the rate of reaction?

Accepted Answer

The reaction is exothermic (ΔH=-13kJmol⁻¹), so the energy profile shows products at a lower energy level than reactants.
Rate = change in concentration / time taken = 0.002/80 = 2.5x10⁻⁵ moldm⁻³s⁻¹.

WAEC Chemistry 2011 Theory — Question 27

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