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Chemistry · THERMODYNAMICS
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Chemistry · THERMODYNAMICS
For the dissociation \( \text{N}_2\text{O}_4(g) \rightleftharpoons 2\text{NO}_2(g) \) at \( 333\text{ K} \) where \( K_p = 1.33\text{ atm} \), what is \( \Delta_r G^\circ \)? (Given: \( R = 8.314\text{ J K}^{-1}\text{mol}^{-1} \), \( \ln(1.33) = 0.285 \))
Read answer →Chemistry · THERMODYNAMICS
Given the standard enthalpies of formation: \( \Delta_f H^\ominus[\text{CO}(g)] = -110.53\text{ kJ mol}^{-1} \) and \( \Delta_f H^\ominus[\text{CO}_2(g)] = -393.51\text{ kJ mol}^{-1} \). The standard enthalpy change (\( \Delta_r H^\ominus \)) for the reaction \( \text{CO}(g) + \frac{1}{2}\text{O}_2(g) \rightarrow \text{CO}_2(g) \) is:
Read answer →Chemistry · THERMODYNAMICS
Calculate \( \Delta_r H^\ominus \) for the reaction: \( \text{Fe}_2\text{O}_3(s) + 3\text{H}_2(g) \to 2\text{Fe}(s) + 3\text{H}_2\text{O}(l) \). Given: \( \Delta_f H^\ominus(\text{H}_2\text{O}, l) = -285.83\text{ kJ mol}^{-1} \) and \( \Delta_f H^\ominus(\text{Fe}_2\text{O}_3, s) = -824.2\text{ kJ mol}^{-1} \).
Read answer →Chemistry · THERMODYNAMICS
Which of the following is an intensive property of a thermodynamic system?
Read answer →Chemistry · THERMODYNAMICS
Which of the following thermodynamic quantities is NOT a state function?
Read answer →Chemistry · THERMODYNAMICS
One mole of liquid water is vaporised at 1 bar pressure and \( 100^\circ\text{C} \). Given that the enthalpy of vaporisation of water is \( 41.00\text{ kJ mol}^{-1} \) and \( R = 8.3\text{ J mol}^{-1}\text{ K}^{-1} \), the change in internal energy (\( \Delta U \)) for the vaporisation of 2.0 moles of water under the same conditions is:
Read answer →Chemistry · THERMODYNAMICS
Consider the following statements regarding thermodynamic spontaneity and enthalpy: (A) A decrease in enthalpy is an absolute and sole criterion for spontaneity in all chemical reactions. (B) Endothermic reactions can be spontaneous if they proceed with an increase in entropy or disorder. (C) In an isolated system, spontaneous processes are driven by a tendency of the system's energy to become more disordered or chaotic. (D) Diffusion of two gases into each other in an isolated vessel occurs with \( \Delta H = 0 \) and is a spontaneous process. How many of the above statements are correct?
Read answer →Chemistry · THERMODYNAMICS
Consider the following enthalpy changes of solution of gaseous \( \text{HCl} \): \( \text{HCl(g)} + 25\text{ aq} \rightarrow \text{HCl}\cdot 25\text{ aq};\; \Delta H = -72.03\text{ kJ mol}^{-1} \) \( \text{HCl(g)} + 40\text{ aq} \rightarrow \text{HCl}\cdot 40\text{ aq};\; \Delta H = -72.79\text{ kJ mol}^{-1} \) The enthalpy of dilution for adding \( 15\text{ mol} \) of water to a solution containing \( 1\text{ mol} \) of \( \text{HCl} \) in \( 25\text{ mol} \) of water is:
Read answer →Chemistry · THERMODYNAMICS
One mole of an ideal gas at \( 300\text{ K} \) is expanded isothermally and reversibly from an initial volume \( V_1 \) to a final volume \( V_2 \) such that \( w = -5.74\text{ kJ} \). If the same gas is expanded irreversibly against a constant external pressure of \( 1\text{ bar} \) between the same initial and final volumes, where \( V_1 = 2.48\text{ L} \), what is the value of \( w_{\text{irrev}} \)? (Take \( R = 8.314\text{ J}\cdot\text{K}^{-1}\cdot\text{mol}^{-1} \), \( \ln 10 = 2.303 \), \( 1\text{ L}\cdot\text{bar} = 100\text{ J} \))
Read answer →Chemistry · THERMODYNAMICS
Given below are two statements: Statement I: The magnitude of enthalpy of vaporisation depends primarily on the strength of intermolecular forces in the liquid. Statement II: Water has a higher standard enthalpy of vaporisation than acetone because of strong intermolecular hydrogen bonding in water. In the light of the above statements, choose the most appropriate answer from the options given below:
Read answer →Chemistry · THERMODYNAMICS
Consider the following statements regarding the Born-Haber cycle for \( \text{NaCl(s)} \): (A) Sublimation of metallic sodium is an endothermic step. (B) Ionization of gaseous sodium atoms to \( \text{Na}^+(\text{g}) \) is an exothermic step. (C) Dissociation of \( \text{Cl}_2(\text{g}) \) molecules into \( \text{Cl}(\text{g}) \) atoms is an endothermic step. (D) Electron gain by \( \text{Cl}(\text{g}) \) to form \( \text{Cl}^-(\text{g}) \) is an exothermic step. Which of the above statements are correct?
Read answer →Chemistry · THERMODYNAMICS
Why is the entropy change \( \Delta S \) inversely proportional to temperature \( T \) when heat \( q_{\text{rev}} \) is added to a system?
Read answer →Chemistry · THERMODYNAMICS
Consider the following statements regarding spontaneity and entropy: (A) Natural processes proceed spontaneously in a unidirectional manner. (B) In an isolated system, the system's energy has a tendency to become more disordered or chaotic. (C) Spontaneous physical or chemical changes are always accompanied by an evolution of heat (\( \Delta H < 0 \)). (D) Entropy (\( S \)) is a thermodynamic function that serves as a measure of disorder or randomness in a system. How many of the above statements are correct?
Read answer →Chemistry · THERMODYNAMICS
Given below are two statements: Statement I: A spontaneous process is always reversible and can be driven in the reverse direction without external agency. Statement II: The First Law of Thermodynamics places no restriction on the direction of heat flow. In the light of the above statements, choose the most appropriate answer from the options given below:
Read answer →Chemistry · THERMODYNAMICS
The standard enthalpy of combustion of glucose, \( \text{C}_6\text{H}_{12}\text{O}_6(s) \), is \( -2802.0\text{ kJ mol}^{-1} \). A person requires \( 8406\text{ kJ} \) of energy per day. What minimum mass of glucose must be consumed by the person to meet this energy demand via combustion?
Read answer →Chemistry · THERMODYNAMICS
Given below are two statements: Statement I: In an exothermic reaction, the system loses heat to the surroundings, and therefore \( \Delta_r H \) is positive. Statement II: In an endothermic reaction, heat is absorbed from the surroundings, and therefore \( \Delta_r H \) is negative. In the light of the above statements, choose the most appropriate answer from the options given below:
Read answer →Chemistry · THERMODYNAMICS
The lattice enthalpy of \( \text{NaCl}(s) \) is \( +788\text{ kJ mol}^{-1} \) and its enthalpy of hydration (\( \Delta_{\text{hyd}} H^\ominus \)) is \( -784\text{ kJ mol}^{-1} \). What is the standard enthalpy of solution (\( \Delta_{\text{sol}} H^\ominus \)) when \( 2\text{ moles} \) of \( \text{NaCl}(s) \) are completely dissolved in excess water?
Read answer →Chemistry · THERMODYNAMICS
For electron gain by a gaseous atom, \( \text{X}(g) + e^- \rightarrow \text{X}^-(g) \), the electron affinity at \( 0\text{ K} \) is \( A = 345.0\text{ kJ mol}^{-1} \). What is the electron gain enthalpy \( \Delta_{eg} H^\ominus \) at \( 298.15\text{ K} \)? (Given \( \frac{5}{2}RT = 6.20\text{ kJ mol}^{-1} \))
Read answer →Chemistry · THERMODYNAMICS
Multiplying the total entropy change expression by \( -T \) gives \( -T\Delta S_{\text{total}} = \Delta H_{\text{sys}} - T\Delta S_{\text{sys}} \). Under constant \( T \) and \( p \), spontaneity requires \( \Delta S_{\text{total}} > 0 \), which corresponds to:
Read answer →Chemistry · THERMODYNAMICS
For a chemical reaction involving ideal gases at constant temperature and pressure, the relation between enthalpy change (\( \Delta H \)) and internal energy change (\( \Delta U \)) is:
Read answer →Chemistry · THERMODYNAMICS
Two litres of an ideal gas at a pressure of \( 10\text{ atm} \) expands isothermally at \( 25^\circ\text{C} \) into a vacuum until its total volume becomes \( 10\text{ litres} \). The heat absorbed (\( q \)) and work done (\( w \)) in this expansion are respectively:
Read answer →Chemistry · THERMODYNAMICS
An ideal gas undergoes compression in two stages: First, against a constant pressure of \( 2.0\text{ atm} \) from \( 10\text{ L} \) to \( 6\text{ L} \), and Second, against a constant pressure of \( 4.0\text{ atm} \) from \( 6\text{ L} \) to \( 3\text{ L} \). The total work done on the gas in litre-atmospheres is:
Read answer →Chemistry · THERMODYNAMICS
