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A gas (C(v.m)=(5)/(2)R) behaving ideall...

A gas `(C_(v.m)=(5)/(2)R)` behaving ideally was allowed to expand reversibly and adiabatically from 1 liter to
32 liter . It's initial at temperature was `327^(@)` C . The molar enthalpy changes `("in "J//"mole")` for the process is

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To solve the problem, we need to find the molar enthalpy change (ΔHm) for a gas that expands reversibly and adiabatically from 1 liter to 32 liters, starting at a temperature of 327°C. The specific heat at constant volume (Cv) is given as (5/2)R. ### Step-by-step Solution: 1. **Convert Initial Temperature to Kelvin:** \[ T_1 = 327°C = 327 + 273 = 600 \, K \] **Hint:** Remember to convert Celsius to Kelvin by adding 273. 2. **Calculate Cp (Specific Heat at Constant Pressure):** \[ C_p = C_v + R = \frac{5}{2}R + R = \frac{5}{2}R + \frac{2}{2}R = \frac{7}{2}R \] **Hint:** Use the relationship \( C_p = C_v + R \) to find Cp. 3. **Determine the Ratio of Volumes:** \[ V_1 = 1 \, L, \quad V_2 = 32 \, L \] \[ \frac{V_1}{V_2} = \frac{1}{32} \] **Hint:** Identify the initial and final volumes to find their ratio. 4. **Calculate the Value of γ (Gamma):** \[ \gamma = \frac{C_p}{C_v} = \frac{\frac{7}{2}R}{\frac{5}{2}R} = \frac{7}{5} \] **Hint:** Use the formula \( \gamma = \frac{C_p}{C_v} \) to find gamma. 5. **Use the Adiabatic Relation to Find T2:** \[ \frac{T_2}{T_1} = \left(\frac{V_1}{V_2}\right)^{\gamma - 1} = \left(\frac{1}{32}\right)^{\frac{7}{5} - 1} = \left(\frac{1}{32}\right)^{\frac{2}{5}} \] \[ T_2 = T_1 \left(\frac{1}{32}\right)^{\frac{2}{5}} = 600 \left(\frac{1}{32}\right)^{\frac{2}{5}} \] **Hint:** Use the adiabatic process relation \( T_2 = T_1 \left(\frac{V_1}{V_2}\right)^{\gamma - 1} \). 6. **Calculate \( T_2 \):** \[ T_2 = 600 \times \left(\frac{1}{32}\right)^{0.4} = 600 \times \frac{1}{4} = 150 \, K \] **Hint:** Simplify the calculation step by step, ensuring to evaluate the exponent correctly. 7. **Calculate the Change in Temperature (ΔT):** \[ \Delta T = T_2 - T_1 = 150 \, K - 600 \, K = -450 \, K \] **Hint:** Remember that ΔT is the final temperature minus the initial temperature. 8. **Calculate the Molar Enthalpy Change (ΔHm):** \[ \Delta H_m = C_p \Delta T = \frac{7}{2}R \times (-450) \] \[ \Delta H_m = -1575R \, J/mole \] **Hint:** Substitute the values of Cp and ΔT into the enthalpy change formula. ### Final Answer: \[ \Delta H_m = -1575R \, J/mole \]

To solve the problem, we need to find the molar enthalpy change (ΔHm) for a gas that expands reversibly and adiabatically from 1 liter to 32 liters, starting at a temperature of 327°C. The specific heat at constant volume (Cv) is given as (5/2)R. ### Step-by-step Solution: 1. **Convert Initial Temperature to Kelvin:** \[ T_1 = 327°C = 327 + 273 = 600 \, K \] ...
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