Question

A first order reaction has rate constant of 1.15*10 -3 s -1 . how long will 5g of this reaction take to reduce to 3g

Answer 1

Hey !!

Given, [R]₀ = 5 g , [R] = 3 g , k = 1.15 × 10⁻³ s⁻¹. As the reaction is of first order

         t = 2.303 / k log [R]₀ / [R] = 2.303 / 1.15 × 10⁻³ s⁻¹ log 5g/3g = 2.00 × 10³ ( log 1.667 )s

        = 2.0 × 10³ × 0.2219 s

        = 443.8 s

        = 444 s

Hope it helps you !