Question

which reaction is an example of a balanced endothermic reaction? answer options: select one of four \\(\ce{n_{2} (g) + o_{2} (g) + heat -> 2no (g)}\\) \\(\ce{n_{2} (g) + o_{2} (g) + heat -> 2n (g)}\\) \\(\ce{n_{2} (g) + o_{2} (g) -> 2no (g)}\\) \\(\ce{n_{2} (g) + o_{2} (g) - heat -> 2no (g)}\\)

Explanation:

1. Endothermic Reaction: In an endothermic reaction, heat is absorbed, so heat should be on the reactant side (left side of the arrow).
2. Balanced Reaction: The number of each type of atom on the reactant side must equal the number on the product side.

• For the first option: $\ce{N_{2}(g) + O_{2}(g) + heat -> 2NO(g)}$
• Reactants: 2 N (from $\ce{N_{2}}$), 2 O (from $\ce{O_{2}}$)
• Products: 2 N (from $2\ce{NO}$), 2 O (from $2\ce{NO}$)
• Heat is on the reactant side (endothermic), and the reaction is balanced.
• Second option: $\ce{N_{2}(g) + O_{2}(g) + heat -> 2N(g)}$ has 2 O on reactant side and 0 on product side (unbalanced).
• Third option: $\ce{N_{2}(g) + O_{2}(g) -> 2NO(g)}$ is balanced but has no heat on reactant side (not endothermic as written).
• Fourth option: $\ce{N_{2}(g) + O_{2}(g) - heat -> 2NO(g)}$ has heat subtracted (exothermic behavior, not endothermic).

Answer:

A. $\ce{N_{2}(g) + O_{2}(g) + heat -> 2NO(g)}$