De acuerdo con la Ley de la Conservación de la Materia postulada por Lavoisier, ¿cuál ecuación química está balanceada? A C2H5OH(l) + O2(g) → CO2 + H2O B C2H5OH(l) + O2(g) → 2CO2 + H2O C C2H5OH(l) + 3O2(g) → 2CO2 + 3H2O D C2H5OH(l) + O2(g) → 2CO2 + 3H2O E 2C2H5OH(l) + 3O2(g) → 2CO2 + 3H2O

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