Which of the following statements concerning the reaction shown below are true?

P4 (s) + 3O2 (g) → P4O6 (s) ∆H = -1640 kJ

I. heat is absorbed
II. heat is released
III. rxn is exothermic
IV. rxn is endothermic
V. products have higher enthalpy content than reactants
VI. reactants have higher enthalpy content than products

I, III, and V

II, III, and V

II, III, and VI

I and III

Question

Which of the following statements concerning the reaction shown below are true?

P4 (s) + 3O2 (g) → P4O6 (s)      ∆H = -1640 kJ

I. heat is absorbed
II. heat is released
III. rxn is exothermic
IV. rxn is endothermic
V. products have higher enthalpy content than reactants
VI. reactants have higher enthalpy content than products
		
I, III, and V
		
II, III, and V
		
II, III, and VI
		
I and III

anonymous · Answer

@TheSmartOne

thesmartone · Answer

Welcome to OpenStudy! @Axelv23

I'm not that great in Chemistry; however @Australopithecus @aaronq @matt101 can assist you better :)

dtan5457 · Answer

Since the delta H (enthalpy) is negative, this is an exothermic reaction, so heat must be RELEASED. 

The reactants will have more enthalpy then the products, as that is when the heat has not yet been released yet, so they are hotter.

matt101 · Answer

I agree with what @dtan5457 said above.

Just to clarify the second sentence, the energy being released isn't coming from the reactants being "hotter" in terms of temperature. Rather, the energy is coming from the bonds themselves (a form of internal energy). You know that in a chemical reaction, bonds are broken and formed to produce new compounds. In the case of an exothermic reaction, the total energy contained in the bonds of the reactants is higher than that contained in the bonds of the products, and the excess energy is released during the reaction as heat (corresponding to the enthalpy change).

Based on this information, @Axelv23, which answer do you think is correct?