the enthalpy of combustion for octane (c8h18(l)), a key component of gasoline, is -5074 kj/mol. the reaction…

the enthalpy of combustion for octane (c8h18(l)), a key component of gasoline, is -5074 kj/mol. the reaction equation is: c8h18(l) + 12.5o2(g) → 8co2(g) + 9h2o(g). what is the δhf for this reaction? 16co2(g) + 18h2o(g) → 2c8h18(l) + 25o2(g) kj done

the enthalpy of combustion for octane (c8h18(l)), a key component of gasoline, is -5074 kj/mol. the reaction equation is: c8h18(l) + 12.5o2(g) → 8co2(g) + 9h2o(g). what is the δhf for this reaction? 16co2(g) + 18h2o(g) → 2c8h18(l) + 25o2(g) kj done

Answer

Explanation:

Step1: Identify the relationship

The first - given reaction is $C_8H_{18}(l)+12.5O_2(g)\rightarrow8CO_2(g)+9H_2O(g)$ with $\Delta H_1=- 5074\ kJ/mol$. The second reaction $16CO_2(g)+18H_2O(g)\rightarrow2C_8H_{18}(l)+25O_2(g)$ is the reverse of the first reaction multiplied by 2.

Step2: Calculate the enthalpy change

When a reaction is reversed, the sign of the enthalpy change is reversed. When a reaction is multiplied by a factor $n$, the enthalpy change is also multiplied by the same factor $n$. For the reverse of the first reaction, the enthalpy change is $\Delta H'_1 = 5074\ kJ/mol$. When we multiply this reversed reaction by 2, the enthalpy change $\Delta H$ for the second reaction is $\Delta H = 2\times5074\ kJ/mol$. $\Delta H=10148\ kJ$

Answer:

$10148$