II. Resuelve los siguientes ejercicios (consulta La tabla entalpias estándar de formación, que se encuentra en el apartado de documentos digitales) 1. Calcula la entalpia de reacción del siguiente proceso y menciona si es una reacción endotérmica o exotérmica.
2NO(g) + O 2(g) → 2NO 2 (g)

For all the people that don't speak this language This is what it says.

Solve the following exercises (see The standard formation enthalpies table, found in the digital documents section)

1. Calculate the enthalpy of the reaction for the following process and state whether it is an endothermic or exothermic reaction

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g

personal, she chose to do it.