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

Reactant Favored - If there are more reactants than products then the reaction is reactants favored.

Product Favored - If there are more products than reactants after the reaction is completed then it is product favored.

Answer 1) Reactant favored

Explanation : 2
`A_((g))` +3
`B_((g))`----> 4
`C_((g))` ΔH = -95 KJ

It is easily observed that the reactant has 5 moles in total whereas the product has only 4 moles. There fore, the number of reactant is more than the products. Hence, it is reactant favored reaction.

Answer 2) Reactant favored

Explanation : 2
`A_((g))`+ 2
`B_((g))`---> 3
`C_((g))` ΔH = 254 KJ.

The total number of moles in reactant side are 2+2 =4 and in products side it has 3 moles only. This shows that products has less moles than reactants, and hence it is reactant favored reaction.

Answer 3) Product favoured

Explanation : 2
`A_((g))`+
`B_((g))`---> 4
`C_((g))` Δ H = 322 KJ

The total number of moles in reactant are 3=2+1=3 and the number of moles in products is 4. Which shoes that the number of moles in products is more than the reactants. This shows that it is product favored.

Answer 4) Product favored

Explanation : 2
`A_((g))`+
`B_((g))`----> 3
`C_((g))` ΔH = -193 KJ

This is a product favored reaction as there are equal number of moles which are formed from reactants to products which is 3. But in this case, we can consider the ΔH is negative which is -193 KJ which shows that the reaction is product favored. And it shows that it is spontaneous in nature.