Consider the following equations: 3 A+6 B ⟶ 3 D ΔH =-403 kJ / mol E+2 F ⟶A

step 1 Okay, let's take this step by step. First, let's write all of the chemical reactions that are gi

Consider the following equations: 3 A+6 B ⟶ 3 D ΔH...

Consider the following equations: $$ \begin{aligned} 3 \mathrm{~A}+6 \mathrm{~B} \longrightarrow & 3 \mathrm{D} & \Delta H &=-403 \mathrm{~kJ} / \mathrm{mol} \\ \mathrm{E}+2 \mathrm{~F} & \longrightarrow \mathrm{A} & \Delta H &=-105.2 \mathrm{~kJ} / \mathrm{mol} \\ \mathrm{C} & \longrightarrow \mathrm{E}+3 \mathrm{D} & \Delta H &=+64.8 \mathrm{~kJ} / \mathrm{mol} \end{aligned} $$ Suppose the first equation is reversed and multiplied by $\frac{1}{6}$, the second and third equations are divided by 2, and the three adjusted equations are added. What is the net reaction and what is the overall heat of this reaction?

Consider the following equations:
$$
\begin{aligned}
3 \mathrm{~A}+6 \mathrm{~B} \longrightarrow & 3 \mathrm{D} & \Delta H &=-403 \mathrm{~kJ} / \mathrm{mol} \\
\mathrm{E}+2 \mathrm{~F} & \longrightarrow \mathrm{A} & \Delta H &=-105.2 \mathrm{~kJ} / \mathrm{mol} \\
\mathrm{C} & \longrightarrow \mathrm{E}+3 \mathrm{D} & \Delta H &=+64.8 \mathrm{~kJ} / \mathrm{mol}
\end{aligned}
$$
Suppose the first equation is reversed and multiplied by $\frac{1}{6}$, the second and third equations are divided by 2, and the three adjusted equations are added. What is the net reaction and what is the overall heat of this reaction?

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Key Concepts

Hess's Law

Hess's Law states that the overall enthalpy change of a chemical reaction is the sum of the enthalpy changes of the individual steps into which the reaction can be divided, regardless of the pathway. This principle enables the calculation of reaction enthalpies even when the reaction proceeds through several intermediate steps.

Stoichiometric Scaling

Stoichiometric scaling involves multiplying the coefficients of a balanced chemical equation by a factor, which in turn scales the enthalpy change by the same factor. This is essential for adjusting the amounts of reactants and products in reactions without altering the intrinsic energy changes per mole.

Reaction Reversal

Reversing a chemical reaction switches the roles of the reactants and products, and this operation necessitates changing the sign of the associated enthalpy change. This concept is used to manipulate the reactions so that certain species can be canceled when combining multiple reactions.

Net Reaction Formation

Net reaction formation is the process of combining multiple adjusted chemical reactions such that intermediate species cancel out, resulting in an equation that represents the overall chemical process. The overall enthalpy change is obtained by summing the enthalpy changes of the individual adjusted reactions.

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