[Korokian]

ok i'm not sure if this is correct

Consider the following reaction:
2N2(g) + O2(g)-----> 2N2O(g)      enthalpy change is +163.2kJ
(a) Is the reaction exothermic or endothermic?
(b) Calculate the amount of heat transferred when 25.0 g of N2O(g) forms by this reaction at constant pressure. 
(c) How many grams of nitrogen gas must react to produce an enthalpy change of 5.00 kJ?
(d) How many kilojoules of heat are produced when 10.0 g of N2O(g) is decomposed into N2(g) and O2(g) at constant pressure?

a. endothermic
b. 46.4 kJ
c. 1.717g N2
d. 18.5 kJ

are those correct?

[enahs]

D would be negative, other then that looks good to me.

[Korokian]

you can produce a negative heat?

[enahs]

It is not negative, it is just a sign convention for enthalpy. If you add energy to the system, it is endothermic and the sign is positive. If the reaction releases energy it is exothermic and the sign is negative. The negative sign indicates heat was released by the system to the surroundings.


Note for any balanced chemical equation you have and are given an enthalpy with it, reversing the reaction gives you the same magnitude but opposite sign for the enthalpy.

[Korokian]

yes, okay thanks
i gave you a scooby snack