Question

Where possible, classify these systems as reactant-favored or product-favored at 298 K. If the direction cannot be determined from the information given, classify the reaction as "Insufficient information".a)2A(g) + 3B(g) -->4C(g) delta H = -95kJ b)2A(g) + 2B(g) -->3C(g) delta H = 254kJ c)2A(g) + B(g) --> 4C(g) delta H =322 kJ d)2A(g) + B(g) --> 3C(g) delta H -193kJ I thought that a)reactant favored, b) reactant favored, c) product favored, and d) insufficient information because that in a and b there are more reactant than products and in c there are more products than reactant and d is equal amount. But I got the answer wrong. Could someone explain to me?

Answer 1

a) 2A(g) + 3B(g) -->4C(g) delta H = -95kJ
This reaction is reactants-favored since on the left side we have greater entropy (meaning there is a higher chance that reaction will happen spontaneously) since there are more particles, i.e. (2+3=5) than on the right (i.e. 4)
b) 2A(g) + 2B(g) -->3C(g) delta H = 254kJ
 Again, reactant favored, more particles on the left side and high delta H indicates that the forward reaction requires energy which is not favorable.
c) 2A(g) + B(g) --> 4C(g) delta H =322 kJ
 Insufficient information, more product particles favoring the forward reaction but high delta H indicating endothermic unfavorable reaction.
 d) 2A(g) + B(g) --> 3C(g) delta H -193kJ
Product favored, exothermic reaction even though the number of particles is the same.