Question

question 4
use the standard thermodynamic properties table to calculate \\( \delta h^{\circ} \\) for
the following reaction:
type numbers in the boxes.
8 points
\\ \mathrm{fe}_{2} \mathrm{o}_{3}(s)+3 \mathrm{co}(g) \
ightarrow 2 \mathrm{fe}(s)+3 \mathrm{co}_{2}(g) \\
\\( \mathrm{kj} \\)
question 5
the combustion reaction of 1-pentanol is:
type numbers in the boxes.
10 points
\\ \mathrm{c}_{5} \mathrm{h}_{11} \mathrm{oh}(l)+\frac{15}{2} \mathrm{o}_{2}(g) \
ightarrow 5 \mathrm{co}_{2}(g)+6 \mathrm{h}_{2} \mathrm{o}(l) \\
the heat of combustion of 1 - pentanol is \\( -3331 \mathrm{~kj} / \mathrm{mol} \\). given the following information, calculate
the heat of formation of 1 - pentanol.
\\( \delta h_{f}^{\circ}\left(\mathrm{co}_{2}(g)\
ight)=-393.5 \mathrm{~kj} / \mathrm{mol} \\)
\\( \delta h_{f}^{\circ}\left(\mathrm{h}_{2} \mathrm{o}(l)\
ight)=-285.8 \mathrm{~kj} / \mathrm{mol} \\)
\\( \mathrm{kj} / \mathrm{mol} \\)

Explanation:

Step1: Recall the formula for $\Delta H^{\circ}$

The formula for $\Delta H^{\circ}$ of a reaction is $\Delta H^{\circ}=\sum n\Delta H^{\circ}_{f}(\text{products})-\sum m\Delta H^{\circ}_{f}(\text{reactants})$.

Step2: Find $\Delta H^{\circ}_{f}$ values from standard tables (for Question 4)

For Question 4:

• $\Delta H^{\circ}_{f}(\text{Fe}_2\text{O}_3(s))=-824.2\ \text{kJ/mol}$
• $\Delta H^{\circ}_{f}(\text{CO}(g))=-110.5\ \text{kJ/mol}$
• $\Delta H^{\circ}_{f}(\text{Fe}(s)) = 0\ \text{kJ/mol}$ (since it's an element in its standard state)
• $\Delta H^{\circ}_{f}(\text{CO}_2(g))=-393.5\ \text{kJ/mol}$

Now calculate $\Delta H^{\circ}$:

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Step3: Apply the formula for Question 5

For Question 5:
The combustion reaction is $\text{C}_{5}\text{H}_{11}\text{OH}(l)+\frac{15}{2}\text{O}_{2}(g)\to5\text{CO}_{2}(g)+6\text{H}_{2}\text{O}(l)$
We know $\Delta H^{\circ}_{\text{combustion}}=-3331\ \text{kJ/mol}$ and $\Delta H^{\circ}_{\text{combustion}}=\sum n\Delta H^{\circ}_{f}(\text{products})-\sum m\Delta H^{\circ}_{f}(\text{reactants})$
Since $\Delta H^{\circ}_{f}(\text{O}_{2}(g)) = 0\ \text{kJ/mol}$ (element in standard state)
Let $\Delta H^{\circ}_{f}(\text{C}_{5}\text{H}_{11}\text{OH}(l))=x$

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Answer:

Question 4: $-24.8$
Question 5: $-351.3$