Question

In a reaction, $$2\mathrm{A}⟶\mathrm{Products}$$, the concentration of A decreases from 0.5 mol L⁻¹ to 0.4 mol L⁻¹ in 10 minutes. Calculate the rate during this interval?

Answer 1

Average rate  = ${\displaystyle -\frac{1}{2}\frac{\Delta \left[\text{A}\right]}{\Delta \text{t}}}$

= ${\displaystyle -\frac{1}{2}\frac{{\left[\text{A}\right]}_2-{\left[\text{A}\right]}_1}{{\text{t}}_2-{\text{t}}_1}}$

= ${\displaystyle -\frac{1}{2}\left(\frac{0.4 \text{M}-0.5 \text{M}}{10 \text{min}}\right)}$

= -${\displaystyle \frac{1}{2}\frac{-0.1}{10}}$

= ${\displaystyle -\frac{1}{2}\left(\frac{-0.1 \text{M}}{10 \text{min}}\right)}$

= 5 × 10⁻³ M min⁻¹