The decomposition of hbr(g) into elemental species is found to have a rate constant of 4.2 ×10−3atm s−1. if 2.00 atm of hbr are present initially, how many minutes must elapse to achieve complete conversion into elements (i. e. all hbr(g) is gone)? assume a completely one-way reaction.

7,94 minutes

Explanation:

If the descomposition of HBr(gr) into elemental species have a rate constant, then this reaction belongs to a zero-order reaction kinetics, where the reaction rate does not depend on the concentration of the reactants.

For the zero-order reactions, concentration-time equation can be written as follows:

                                          [A] = - Kt + [Ao]

where:

To solve the problem, we just replace our data in the concentration-time equation, and we clear the value of t.

Data:

K = 4.2 ×10−3atm/s,  

[A]o=[HBr]o= 2 atm,  

[A]=[HBr]=0 atm (all HBr(g) is gone)

We clear the incognita :

[A] = - Kt + [Ao] Kt =  [Ao] - [A]

                                        t  = ([Ao] - [A])/K

We replace the numerical values:

t = (2 atm - 0 atm)/4.2 ×10−3atm/s = 476,19 s = 7,94 minutes

So, we need 7,94 minutes to achieve complete conversion into elements ([HBr]=0).

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.