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.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

am i too late?

explanation: