Answered

A chemist measures the energy change [tex]$\Delta H$[/tex] during the following reaction:
[tex]\[ 2 \text{Fe}_2 \text{O}_3(s) \rightarrow 4 \text{FeO}(s) + \text{O}_2(g) \quad \Delta H = 560 \text{ kJ} \][/tex]

Use the information to answer the following questions.

1. This reaction is:
- A. endothermic
- B. exothermic

2. Suppose 56.3 g of [tex]$\text{Fe}_2 \text{O}_3$[/tex] react. Will any heat be released or absorbed?
- A. Yes, absorbed
- B. Yes, released

3. If you said heat will be released or absorbed in the second part of this question, calculate how much heat will be released or absorbed. Round your answer to 3 significant digits.
[tex]\[ \square \text{ kJ} \][/tex]



Answer :

Sure, let's address each part of the problem step by step:

1. Determine the nature of the reaction:
- The reaction given is:
[tex]$2 Fe_2O_3(s) \rightarrow 4 FeO(s) + O_2(g) \quad \Delta H = 560 \text{ kJ}$[/tex]
- The value of [tex]\(\Delta H\)[/tex] is positive (560 kJ), indicating that the reaction absorbs energy.
- Therefore, the reaction is endothermic.

2. Determine whether heat will be released or absorbed when 56.3 g of [tex]\(Fe_2O_3\)[/tex] reacts:
- Since the reaction is endothermic (as established above), heat will be absorbed.

3. Calculate the amount of heat absorbed:
- First, we need to determine the molar mass of [tex]\(Fe_2O_3\)[/tex].
- The molar mass of [tex]\(Fe\)[/tex] is 55.845 g/mol, and the molar mass of [tex]\(O\)[/tex] is 15.999 g/mol.
- Therefore, the molar mass of [tex]\(Fe_2O_3\)[/tex] is:
[tex]$ \text{Molar mass of } Fe_2O_3 = 2 \times 55.845 + 3 \times 15.999 = 159.687 \text{ g/mol} $[/tex]

- Next, we calculate the number of moles of [tex]\(Fe_2O_3\)[/tex] in 56.3 g:
[tex]$ \text{Moles of } Fe_2O_3 = \frac{56.3 \text{ g}}{159.687 \text{ g/mol}} = 0.3525647047035763 \text{ moles} $[/tex]

- The given heat change ([tex]\(\Delta H\)[/tex]) is for 2 moles of [tex]\(Fe_2O_3\)[/tex], and [tex]\(\Delta H\)[/tex] for the reaction is 560 kJ. Therefore, the heat change per mole of [tex]\(Fe_2O_3\)[/tex] is:
[tex]$ \Delta H \text{ per mole} = \frac{560 \text{ kJ}}{2 \text{ moles}} = 280 \text{ kJ/mol} $[/tex]

- To find the heat change for the given moles of [tex]\(Fe_2O_3\)[/tex] (0.3525647047035763 moles), we multiply the moles by the heat change per mole:
[tex]$ \text{Heat change} = 0.3525647047035763 \text{ moles} \times 280 \text{ kJ/mol} = 98.718 \text{ kJ} $[/tex]

4. Final conclusion:
- The heat absorbed by the reaction when 56.3 g of [tex]\(Fe_2O_3\)[/tex] reacts is [tex]\( 98.718 \text{ kJ} \)[/tex].


Therefore, the detailed step-by-step solution is:

\begin{tabular}{|l|l|}
\hline This reaction is... & \textbf{endothermic.} \\
\hline Suppose 56.3 g of [tex]$Fe_2 O_3$[/tex] react. & \textbf{Yes, absorbed.} \\
\hline \begin{tabular}{l}
If you said heat will be released or absorbed in \\
the second part of this question, calculate how \\
much heat will be released or absorbed.
\end{tabular} & \\
\hline Round your answer to 3 significant digits. & [tex]\(\boxed{98.7 \text{ kJ}}\)[/tex] \\
\hline
\end{tabular}