Whether the condition of phase transition in reusable hot-packs, which use the precipitation of super saturated sodium acetate or calcium acetate to give off heat of crystallization to warm a person, can be understood in terms of Clapeyron or the Clausius-Clapeyron equation is to be stated. The reason for the same is to be stated. Concept introduction: Clapeyron equation represents the relation between the change in pressure and temperature for all the phases involved to the change in entropies and molar volumes. The Clausius-Clapeyron equation can be obtained from the rearrangement and integration of Clapeyron equation. The Clausius-Clapeyron equation is generally used for gas-phase equilibria, to predict the equilibrium temperatures and pressures and also for the determination of enthalpy for phase transition.

Question

A student obtained a solid product in a laboratory synthesis. To verify the identity of the solid, she measured its melting point and found that the material melted over a 12 degrees Celsius range. After it had cooled, she measured the melting point of the same sample again and found that this time the solid had a sharp melting point at the temperature that is characteristic of the desired product. Why were the two melting points different? What was responsible for the change in the melting point?

Answer 1

Question

Chapter 6, Problem 6.32E

Interpretation Introduction

Interpretation:

Whether the condition of phase transition in reusable hot-packs, which use the precipitation of super saturated sodium acetate or calcium acetate to give off heat of crystallization to warm a person, can be understood in terms of Clapeyron or the Clausius-Clapeyron equation is to be stated. The reason for the same is to be stated.

Concept introduction:

Clapeyron equation represents the relation between the change in pressure and temperature for all the phases involved to the change in entropies and molar volumes.

The Clausius-Clapeyron equation can be obtained from the rearrangement and integration of Clapeyron equation. The Clausius-Clapeyron equation is generally used for gas-phase equilibria, to predict the equilibrium temperatures and pressures and also for the determination of enthalpy for phase transition.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Students have asked these similar questions

A student obtained a solid product in a laboratory synthesis. To verify the identity of the solid, she measured its melting point and found that the material melted over a 12 degrees Celsius range. After it had cooled, she measured the melting point of the same sample again and found that this time the solid had a sharp melting point at the temperature that is characteristic of the desired product. Why were the two melting points different? What was responsible for the change in the melting point?

Given that the normal boiling point of CH3CH2CH2CH2NH2 is 77 °C, which of the following statements about the process below is/are correct? You may choose more than one, or none, of the statements. CH3CH2CH2CH2NH2(g, 96 °C, 1 atm) ⟶ CH3CH2CH2CH2NH2(l, 63 °C, 1 atm) You may assume that the temperature of the surroundings is constant and also equal to 63 °C. Note: The normal boiling point (Tnbp) is the boiling temperature at 1 atm. The phase change is reversible at the normal boiling point but irreversible if P = 1 atm and T ≠ Tnbp. The entropy of the system increases: ΔS > 0. The entropy of the surroundings increases: ΔSsurr > 0. The entropy of the universe increases: ΔSuniv > 0. Work is done by the system on the surroundings. Heat flows from the system into the surroundings. The entropy change for the system is equal to ΔH / Tvap. The entropy change for the system is equal to ΔH / Tsurr.…

Determine the enthalpy of vaporization at 343.15 K for water. (Note: The heat of vaporization for water is known to be 40.79 kJ mol-1 at 273.15 K, the Cp of water (Liq) was determined to be 85.6 J K-1 mol-1 and the Cp of water (solid) was to be 54.35 J K-1 mol-1). Use the reaction below and give your final answer in kJ mol-1. H2O(solid, 273.15 K, 0.1 atm)--------H2O(liq, 273.15 K, 0.1 atm)