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Change in enthalpy and entropy when sugar dissolves in water
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+ Enthalpy
+ Thermodynamics
+ Entropy
+ Chemistry
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M Schoenberger
Change in enthalpy and entropy when sugar dissolves in water
Since solubility of sugar in water increases with temperature, the change in enthalpy of the sugar-water system is positive. Since the sugar-water system is absorbing heat(at constant pressure, change in enthalpy is the heat absorbed) and since entropy change of an irreversible process is greater than that in an reversible process, the entropy of the sugar-water system will increase. So at constant temperature and pressure the enthalpy change is positive, entropy change is positive and the the change in Gibbs free energy is negative(before equilibrium is attained) . The process is spontaneous. By the time the system reaches equilibrium the enthalpy change will have been balanced by the change in entropy and so the change in Gibbs free energy is 0.
Since solubility of sugar in water increases with temperature, the change in enthalpy of the sugar-water system is positive. Since the sugar-water system is absorbing heat(at constant pressure, change in enthalpy is the heat absorbed) and since entropy change of an irreversible process is greater than that in an reversible process, the entropy of the sugar-water system will increase. So at constant temperature and pressure the enthalpy change is positive, entropy change is positive and the the change in Gibbs free energy is negative(before equilibrium is attained) . The process is spontaneous. By the time the system reaches equilibrium the enthalpy change will have been balanced by the change in entropy and so the change in Gibbs free energy is 0.
Since solubility of sugar in water increases with temperature, the change in enthalpy of the sugar-water system is positive. Since the sugar-water system is absorbing heat(at constant pressure, change in enthalpy is the heat absorbed) and since entropy change of an irreversible process is greater than that in an reversible process, the entropy of the sugar-water system will increase. So at constant temperature and pressure the enthalpy change is positive, entropy change is positive and the the change in Gibbs free energy is negative(before equilibrium is attained) . The process is spontaneous. By the time the system reaches equilibrium the enthalpy change will have been balanced by the change in entropy and so the change in Gibbs free energy is 0.
Since solubility of sugar in water increases with temperature, the change in enthalpy of the sugar-water system is positive. Since the sugar-water system is absorbing heat(at constant pressure, change in enthalpy is the heat absorbed) and since entropy change of an irreversible process is greater than that in an reversible process, the entropy of the sugar-water system will increase. So at constant temperature and pressure the enthalpy change is positive, entropy change is positive and the the change in Gibbs free energy is negative(before equilibrium is attained) . The process is spontaneous. By the time the system reaches equilibrium the enthalpy change will have been balanced by the change in entropy and so the change in Gibbs free energy is 0.
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The entropy change for ideal mixing is $\Delta S=-R(x_A\ln{x_A}+x_B\ln{x_B})$
The entropy change for ideal mixing is $\Delta S=-R(x_A\ln{x_A}+x_B\ln{x_B})$
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