Consider the general reversible reaction. aA + bB _ > C + dD
What is the equilibrium constant expression for the given system?
O keq
O Keq =
c[C]d[D]
a[A]b[B]
[C][D]
[A][B]
Keq =
[A]*[B]
[C][Dd
[C]°[]"
Keq =
[A]”[B]"

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