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A chart is prepared by plotting In Ksp versus 1/T, using data obtained by performing a lab experiment. Refer to the attached photo for guidance on how to perform these calculations; Equation 5 is particularly useful. A linear fit of the data in the chart yields the equation y = (-4.976x10^3)x+(1.9900x10^1) with an R2 value of 0.9922. Determine the entropy (deltaS in J/K) associated with dissolving KNO3. Answer in scientific notation with appropriate sigfigs.

A chart is prepared by plotting In Ksp versus 1/T, using data obtained by performing a lab experiment. Refer to the attached photo for guidance on how to perform these calculations; Equation 5 is particularly useful. A linear fit of the data in the chart yields the equation y = (-4.976x10^3)x+(1.9900x10^1) with an R2 value of 0.9922. Determine the entropy (deltaS in J/K) associated with dissolving KNO3. Answer in scientific notation with appropriate sigfigs.

Chemistry
Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
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Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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A chart is prepared by plotting In Ksp versus 1/T, using data obtained by performing a lab experiment. Refer to the attached photo for guidance on how to perform these calculations; Equation 5 is particularly useful.

A linear fit of the data in the chart yields the equation y = (-4.976x10^3)x+(1.9900x10^1) with an R2 value of 0.9922. Determine the entropy (deltaS in J/K) associated with dissolving KNO3.

Answer in scientific notation with appropriate sigfigs.

Thermodynamics may be used to understand what energy changes occur when a salt dissolves in water. The energy difference between the solid salt and its dissolved ions is known as the enthalpy change (AH), and the relative disorder of the dissolved ions is an indication of the entropy change (AS). A positive enthalpy change will occur if heat must be added to dissolve the salt in water. The enthalpy change will be negative if the dissolution process releases heat. The entropy change for a solid salt dissolving in water should be positive because the dissolved ions possess more disorder than a solid salt molecule. The free energy change (AG) for a salt dissolving in water indicates whether the process will occur spontaneously. A negative free energy change implies that the salt will spontaneously dissolve in water while a positive free energy change indicates that the process is non-spontaneous. The Gibbs-Helmholtz equation, shown in equation (2), is a mathematical relationship between the changes in free energy, enthalpy, and entropy. ΔG -ΔΗ-ΤAS (2) A mathematical relationship, shown in equation (3) also exists between the free energy change and the solubility equilibrium constant. AG = -RTInKsp (3) %3D In equation (3), R is the gas constant (8.314 J/mol·K), and T is the temperature in Kelvin. The change in free energy for a reaction is dependent on temperature just as is the equilibrium constant. By substituting the equilibrium constant relationship in to the Gibbs-Helmholtz equation, equation (4) results. -RTINKSP -ΔΗ-ΤAS (4) By using algebra, it is possible to rearrange equation (4) into the form of a straight line as shown in equation (5). (5) AS + R AH In Kp R By plotting In Ksp versus 1/T, the slope of the line is -AH/R and the y-intercept is AS/R. By evaluating the temperature dependence of the solubility equilibrium constant, the enthalpy and entropy of dissolution can be determined.
Transcribed Image Text:Thermodynamics may be used to understand what energy changes occur when a salt dissolves in water. The energy difference between the solid salt and its dissolved ions is known as the enthalpy change (AH), and the relative disorder of the dissolved ions is an indication of the entropy change (AS). A positive enthalpy change will occur if heat must be added to dissolve the salt in water. The enthalpy change will be negative if the dissolution process releases heat. The entropy change for a solid salt dissolving in water should be positive because the dissolved ions possess more disorder than a solid salt molecule. The free energy change (AG) for a salt dissolving in water indicates whether the process will occur spontaneously. A negative free energy change implies that the salt will spontaneously dissolve in water while a positive free energy change indicates that the process is non-spontaneous. The Gibbs-Helmholtz equation, shown in equation (2), is a mathematical relationship between the changes in free energy, enthalpy, and entropy. ΔG -ΔΗ-ΤAS (2) A mathematical relationship, shown in equation (3) also exists between the free energy change and the solubility equilibrium constant. AG = -RTInKsp (3) %3D In equation (3), R is the gas constant (8.314 J/mol·K), and T is the temperature in Kelvin. The change in free energy for a reaction is dependent on temperature just as is the equilibrium constant. By substituting the equilibrium constant relationship in to the Gibbs-Helmholtz equation, equation (4) results. -RTINKSP -ΔΗ-ΤAS (4) By using algebra, it is possible to rearrange equation (4) into the form of a straight line as shown in equation (5). (5) AS + R AH In Kp R By plotting In Ksp versus 1/T, the slope of the line is -AH/R and the y-intercept is AS/R. By evaluating the temperature dependence of the solubility equilibrium constant, the enthalpy and entropy of dissolution can be determined.
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