Calculating Heat of Solution for CaCl2 & NaHCO3: Equations and Solutions

[jessica.so]

Homework Statement

What is the heat of solution of calcium chloride (CaCl2) and sodium bicarbonate (NaHCO3)?

Homework Equations

The Attempt at a Solution

Heat of solution is more formally known as the enthalpy of fusion. I tried googling this but I am not sure if this is the correct answer...
Heat of solution of CaCl2: -81.3 kJ/mol
Heat of solution of NaHCO3: +33 kJ/mol

Any help is appreciated! Any websites with such information would be awesome!

 

[Borek]

Heat of solution is more formally known as the enthalpy of fusion.

No, dissolution and fusion are two separate processes. Heat of solution is heat that evolves during dissolution of a substance (usually in water). Heat of fusion is amount of heat required to melt the substance.

 

[jessica.so]

Okay. Is the heat of solution a value that I need to calculate that has a formula? Or should I be able to find a list that lists all of them?

 

[Borek]

Basically these are determined experimentally. If some other data is known it can be possible to calculate heat of dissolution from the Hess law, but the same can be told about every other process.

 

[DeeNos]

The heat of solution, also known as the enthalpy of solution, is the amount of energy absorbed or released when a substance dissolves in a solvent. In the case of CaCl2 and NaHCO3, the heat of solution can be calculated using the following equations:

For CaCl2:
ΔHsoln = ΔHhydration + ΔHlattice

ΔHhydration = -81.3 kJ/mol (from experimental data)
ΔHlattice = energy required to break the lattice structure of CaCl2, which can be calculated using the Born-Haber cycle or Hess's law.

For NaHCO3:
ΔHsoln = ΔHhydration + ΔHlattice + ΔHdecomposition

ΔHhydration = +33 kJ/mol (from experimental data)
ΔHlattice = energy required to break the lattice structure of NaHCO3, which can be calculated using the Born-Haber cycle or Hess's law.
ΔHdecomposition = energy released when NaHCO3 decomposes into NaCl, CO2, and H2O, which can also be calculated using Hess's law.

There are many websites and resources available that provide experimental data and calculations for the heat of solution of various substances. Some examples include ChemSpider, NIST Chemistry WebBook, and textbooks on thermodynamics or physical chemistry. It is important to note that the heat of solution may vary depending on the experimental conditions, such as temperature and concentration, so it is best to consult multiple sources for accurate data.