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Consider the following reactions. DeltaH...

Consider the following reactions. `DeltaH^(@)` values of the reactions hve been given as `-x, -y` and z kJ.
`Fe_(3)O_(4)(s) to 3Fe(s) + 2O_(2)(g), DeltaH^(@) = z kJ`
`2Fe(s) + O_(2)(g) to 2FeO(s), DeltaH^(@) =-x kJ`
`4Fe(s) + 3O_(2)(g) to 2Fe_(2)O_(3)(s), DeltaH^(@) =-y kJ`
In the given set of reaction, `-x//2` kJ refers to

A

Heat of formation of FeO(s)

B

Standard heat of formation of FeO(s)

C

Half the heat of formation of FeO(s)

D

All of these are correct.

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the given reactions and their enthalpy changes (ΔH) to determine what the expression -x/2 kJ refers to. ### Step-by-Step Solution: 1. **Identify the Reactions and Their Enthalpy Changes:** - Reaction 1: \( \text{Fe}_3\text{O}_4(s) \rightarrow 3\text{Fe}(s) + 2\text{O}_2(g), \Delta H = z \, \text{kJ} \) - Reaction 2: \( 2\text{Fe}(s) + \text{O}_2(g) \rightarrow 2\text{FeO}(s), \Delta H = -x \, \text{kJ} \) - Reaction 3: \( 4\text{Fe}(s) + 3\text{O}_2(g) \rightarrow 2\text{Fe}_2\text{O}_3(s), \Delta H = -y \, \text{kJ} \) 2. **Understanding the Enthalpy of Formation:** - The standard enthalpy of formation (ΔH_f°) is defined as the enthalpy change when one mole of a compound is formed from its elements in their standard states. 3. **Analyzing Reaction 2:** - The second reaction shows that 2 moles of iron (Fe) react with 1 mole of oxygen (O₂) to form 2 moles of iron(II) oxide (FeO). - The enthalpy change for this reaction is -x kJ. 4. **Dividing the Reaction:** - If we divide the entire reaction by 2, we get: \[ \text{Fe}(s) + \frac{1}{2}\text{O}_2(g) \rightarrow \text{FeO}(s) \] - The enthalpy change for this modified reaction will be: \[ \Delta H = \frac{-x}{2} \, \text{kJ} \] 5. **Conclusion:** - The enthalpy change of -x/2 kJ corresponds to the formation of 1 mole of FeO from its elements (Fe and O₂). - Therefore, -x/2 kJ refers to the standard heat of formation of ferrous oxide (FeO). ### Final Answer: The expression -x/2 kJ refers to the standard heat of formation of ferrous oxide (FeO). ---
To solve the problem, we need to analyze the given reactions and their enthalpy changes (ΔH) to determine what the expression -x/2 kJ refers to. ### Step-by-Step Solution: 1. **Identify the Reactions and Their Enthalpy Changes:** - Reaction 1: \( \text{Fe}_3\text{O}_4(s) \rightarrow 3\text{Fe}(s) + 2\text{O}_2(g), \Delta H = z \, \text{kJ} \) - Reaction 2: \( 2\text{Fe}(s) + \text{O}_2(g) \rightarrow 2\text{FeO}(s), \Delta H = -x \, \text{kJ} \) - Reaction 3: \( 4\text{Fe}(s) + 3\text{O}_2(g) \rightarrow 2\text{Fe}_2\text{O}_3(s), \Delta H = -y \, \text{kJ} \) ...
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