madey21
Answered

An original reaction and enthalpy are given below.

[tex]\[
\begin{array}{r}
Fe_2O_3(s) + 3CO(g) \rightarrow 2Fe(s) + 3CO_2(g) \\
\Delta H = -23.44 \, \text{kJ}
\end{array}
\][/tex]

What is the enthalpy for the altered reaction below?

[tex]\[
\begin{array}{c}
3Fe_2O_3(s) + 9CO(g) \rightarrow 6Fe(s) + 9CO_2(g) \\
\Delta H = [?] \, \text{kJ}
\end{array}
\][/tex]

Enter either a + or - sign and the magnitude. Use significant figures.



Answer :

To solve for the enthalpy change ([tex]\(\Delta H\)[/tex]) of the altered reaction, we need to understand how the enthalpy change scales with the reaction. Here is the step-by-step breakdown:

1. Original Reaction Given:
[tex]\[ Fe_2O_3(s) + 3 CO(g) \rightarrow 2 Fe(s) + 3 CO_2(g) \][/tex]
With an enthalpy change of:
[tex]\[ \Delta H = -23.44 \text{ kJ} \][/tex]

2. Altered Reaction:
[tex]\[ 3 Fe_2O_3(s) + 9 CO(g) \rightarrow 6 Fe(s) + 9 CO_2(g) \][/tex]

3. Comparison Between Reactions:
The altered reaction is exactly three times the original reaction. This can be verified by comparing the coefficients of each substance in both reactions:
- Original reaction: [tex]\(Fe_2O_3\)[/tex] [tex]\(\times 1\)[/tex], [tex]\(CO\)[/tex] [tex]\(\times 3\)[/tex], [tex]\(Fe\)[/tex] [tex]\(\times 2\)[/tex], [tex]\(CO_2\)[/tex] [tex]\(\times 3\)[/tex]
- Altered reaction: [tex]\(Fe_2O_3\)[/tex] [tex]\(\times 3\)[/tex], [tex]\(CO\)[/tex] [tex]\(\times 9\)[/tex], [tex]\(Fe\)[/tex] [tex]\(\times 6\)[/tex], [tex]\(CO_2\)[/tex] [tex]\(\times 9\)[/tex]

4. Determination of Enthalpy Change for the Altered Reaction:
Since the altered reaction is three times the original reaction, the enthalpy change will also be three times the enthalpy change of the original reaction.

5. Calculation:
Multiply the original enthalpy change by 3:
[tex]\[ \Delta H_{\text{altered}} = 3 \times \Delta H_{\text{original}} \][/tex]
[tex]\[ \Delta H_{\text{altered}} = 3 \times (-23.44 \text{ kJ}) \][/tex]
[tex]\[ \Delta H_{\text{altered}} = -70.32 \text{ kJ} \][/tex]

6. Result with Significant Figures:
The given original enthalpy change (-23.44 kJ) has four significant figures, so our final answer should also be presented with the same precision.

Thus, the enthalpy change ([tex]\(\Delta H\)[/tex]) for the altered reaction is:
[tex]\[ \Delta H = -70.32 \text { kJ} \][/tex]