Nitrogen dioxide, NO2(g) (Delta. Hf = 33.84 kJ/mol), is decomposed according to the following reaction:

2 upper N upper O subscript 2 (g) right arrow upper N subscript 2 (g) plus 2 upper O subscript 2 (g).

What is the enthalpy change when 2.50 mol of nitrogen dioxide decomposes?
Use Delta H r x n equals the sum of delta H f of all the products minus the sum of delta H f of all the reactants..

13.5 kJ of energy released
13.5 kJ of energy absorbed
84.6 kJ of energy released
84.6 kJ of energy absorbed

C

Explanation:

84.6 kJ of energy released when 2.50 moles of nitrogen dioxide is decomposed.

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.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.