Chapter 18, Problem 38GQ

Interpretation Introduction

Interpretation:

The balanced equation for formation of $\text{1}\text{mol}{\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}\left(\text{s}\right)$ should be written. The standard free energy change for the formation of $\text{1}\text{mol}{\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}\left(\text{s}\right)$ from its elements and the value of ${\text{ΔG}}^{\text{o}}$ for formation of $\text{454 g}$${\text{Fe}}_{\text{2}}{\text{O}}_{\text{3}}\left(\text{s}\right)$ should be calculated.

Concept introduction:

The Gibbs free energy or the free energy change is a thermodynamic quantity represented by ${\Delta }_{\text{r}}{G}^{\circ }$. It can be calculated in a similar manner as entropy and enthalpy.  The expression for the free energy change is:

  ${\text{Δ}}_{\text{r}}{G}^{\text{°}}=\sum n{\Delta }_f{G}^{\text{°}}\left(\text{products}\right)-\sum n{\Delta }_f{G}^{\text{°}}\left(\text{reactants}\right)$

• Chemical equation is the representation of a chemical reaction, in which the reactants and products of the reactions are represented left and right side of an arrow respectively by using their respective chemical formulas.
• Reactant of a chemical reaction is the substrate compounds or the compounds which undergo a chemical reaction.
• Product of a chemical reaction is the produced compounds or the compounds formed after a chemical reaction.
• Balanced chemical equation of a reaction is written according to law of conservation of mass.

Moles: One mole is equivalent to the mass of the substance consists same number of units equal to the atoms present in $\text{12}\text{g}$ of ${}^{\text{12}}\text{C}$.

From given mass of substance moles could be calculated by using the following formula,

  $\text{Moles}\text{of}\text{substance }\text{= }\frac{\text{Given}\text{mass}\text{of}\text{substance}}{\text{Molecular}\text{mass}}$