Calculate the approximate enthalpy change, δhrxn, for the combustion of one mole of methane a shown in the balanced chemical equation: ch4+2o2→2h2o+co2 use the values you calculated in parts a, b, c, and d, keeping in mind the stoichiometric coefficients

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