Exercise 2 | Chemical Kinetics: Rate Laws

Carbon disulfide breaks down into carbon monosulfide and sulfur at 1000°C.

1) Write the chemical equation of this reaction.

2) Calculate the half-life of this reaction at 1000°C, knowing it is a first-order reaction and k = 2.8 x 10-7 s-1.

 

1) CS2 → CS + S

 

2) At t = t1/2, [A] = [A]0 / 2

⇒ ln [A]02 [A]0 = - kt1/2 

⇒ t1/2ln 2k = ln 22.8 × 10-7

⇒ t1/2 =  2.5 x 106 s