For the simple decomposition reaction AB(g)  A(g) + B(g) rate = k [AB]2 and k = 0.2 L/(mols). How long will it take for [AB] to reach 1/3 of its initial concentration of 1.50 M?

the temperature of the gas, in k, not celsius.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol