Finding Hydration & Solubility of LiI: Endo/Exo?

[Apostle]

Heat of Hydration?

My text asks me to find the (delta H hydration = ? kj/mol ) and
the (delta Hsoln =? kj/mol) when LiI (lithium iodide) is dissolved in water and the solution becomes hotter. Endo/Exo?? And how do I find the kj/mol's. I am a first year student and starting in the middle of the year, so I am a little behind so to speak.
Sorry about any wrong info. This is my first time on this site.

 

[mgb_phys]

Heat of hydration is the energy given out when the Li and I bond with water - This will be pretty exothermic ( energy given out = negative )
Heat of solution is the energy needed to break the LiI into separate ions, this takes energy and is endothermic ( energy taken in = positive )

Be careful though - you could also define the heat of solution to be the total energy generated ie heat hydration + heat solution.
I don't know how you work these out from first principles, you would eithe rmeasure it in an experiment or use values from tables (of other people experiments )

 

[Blueshift5]

Hi there,

First of all, welcome to the scientific community! Don't worry about being a little behind, we all have to start somewhere and it's great that you're seeking help to catch up.

To answer your question, the terms "endo" and "exo" refer to the direction of heat flow in a chemical reaction. Endothermic reactions absorb heat from the surroundings, while exothermic reactions release heat into the surroundings.

In the case of dissolving LiI in water, this is an exothermic reaction. This means that heat is released into the surrounding water as the LiI molecules break apart and interact with the water molecules. Therefore, the change in enthalpy (delta H) for this reaction will be negative, indicating an exothermic process.

To find the delta H for hydration and solubility, you will need to conduct experiments to measure the change in temperature of the water as the LiI dissolves. This change in temperature can then be used to calculate the delta H using the equation delta H = m x c x delta T, where m is the mass of the water, c is the specific heat capacity of water, and delta T is the change in temperature.

I hope this helps and good luck with your studies!