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The value of enthalpy change (DeltaH) fo...

The value of enthalpy change `(DeltaH)` for the reaction
`C_(2)H_(5)OH(l)+3O_(2)(g)rarr2CO_(2)(g)+3H_(2)O(l)`
at `27^(@)C` is `-1366.5KJmol^(-1)` . The value of internal energy change for the above reaction at this tempearature will be

A

`-1371.5KJ`

B

`-1369.0KJ`

C

`-1364.0KJ`

D

`-1361.5KJ`

Text Solution

AI Generated Solution

The correct Answer is:
To find the internal energy change (ΔU) for the reaction given the enthalpy change (ΔH), we can use the relationship between these two thermodynamic quantities: \[ \Delta H = \Delta U + \Delta N_g RT \] Where: - ΔH is the enthalpy change, - ΔU is the internal energy change, - ΔN_g is the change in the number of moles of gas, - R is the universal gas constant (8.314 J/mol·K), - T is the temperature in Kelvin. ### Step-by-Step Solution: 1. **Identify the given values:** - Enthalpy change (ΔH) = -1366.5 kJ/mol - Temperature (T) = 27°C = 27 + 273 = 300 K - R = 8.314 J/mol·K = 0.008314 kJ/mol·K (since we want the final answer in kJ) 2. **Calculate ΔN_g:** - The reaction is: \[ C_{2}H_{5}OH(l) + 3O_{2}(g) \rightarrow 2CO_{2}(g) + 3H_{2}O(l) \] - Count the moles of gaseous reactants and products: - Gaseous products: 2 moles of CO₂ - Gaseous reactants: 3 moles of O₂ - Therefore, ΔN_g = moles of products - moles of reactants = 2 - 3 = -1. 3. **Calculate ΔN_g RT:** \[ \Delta N_g RT = (-1) \times (0.008314 \, \text{kJ/mol·K}) \times (300 \, \text{K}) = -2.4942 \, \text{kJ} \] 4. **Substitute values into the equation:** \[ \Delta U = \Delta H - \Delta N_g RT \] \[ \Delta U = -1366.5 \, \text{kJ/mol} - (-2.4942 \, \text{kJ}) \] \[ \Delta U = -1366.5 + 2.4942 = -1364.0058 \, \text{kJ/mol} \] 5. **Round the answer:** The internal energy change (ΔU) can be rounded to: \[ \Delta U \approx -1364.0 \, \text{kJ/mol} \] ### Final Answer: The value of internal energy change (ΔU) for the reaction at 27°C is approximately **-1364.0 kJ/mol**.

To find the internal energy change (ΔU) for the reaction given the enthalpy change (ΔH), we can use the relationship between these two thermodynamic quantities: \[ \Delta H = \Delta U + \Delta N_g RT \] Where: - ΔH is the enthalpy change, ...
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A2Z-CHEMICAL THERMODYNAMICS-Section D - Chapter End Test
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  9. Given,H(s)(g)=2H(g)Delta(H-H)=103kcalmol^(-1) CH(4)(g)=CH(3)(g)+H(g...

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  10. For the combustion of n-octane C(8)H(18)+O(2)rarrCO(2)+H(2)O at 25^(...

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  13. If 900J//g of heat is exchanged at boiling point of water then water...

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  14. The enthalpy of formation of H(2)O(l) is -280.70 kJ/mol and enthalpy o...

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  16. Calculate the resonance enegry of N(2)O form the following data Delt...

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  17. If a 298K the bond energies of C-H,C-C,C=C and H-H bonds are respectiv...

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  18. The enthalpies of formation of Al(2)O(3) and Cr(2)O(3) are -1596KJ and...

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  19. "The quanity of heat which must be supplied to decompose a compound in...

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