When 1 mole of h2co(g) reacts with o2(g) to form co2(g) and h2o(l) according to the following equation, 563 kj of energy are evolved. h2co(g) + o2(g)co2(g) + h2o(l) is this reaction endothermic or exothermic? what is the value of q? write a balanced thermochemical equation

This is an exothermic reaction

q = 563 kJ

Explanation:

Step 1: The balanced thermochemical equation

H2CO(g) + O2(g) → CO2(g) + H2O(l)        ΔH = -563 kJ

This is a combustion, this means there will be released heat. This means it's an exothermic reaction.

The energy involved, will be released (that's why ΔH is negative)

q has the same value as ΔH (but positive)

q = 563 kJ

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.