Solution formation exothermic process

Many times, the dissolving process generates heat, which is to say it is exothermic. Occasionally solution formation is endothermic. 

B) The amounts are really meaningless in this problem. The key pieces of information are the words dissolved and that the temperature increases. Because the temperature of the system increases, the dissolving must be an exothermic process, meaning that AH < 0. The sodium hydroxide dissolves in solution, meaning that the crystalline lattice breaks apart into solvated ions. This is a much less orderly formation, which means the entropy has increased. Therefore, AS > 0 in this process. Because the dissolving occurs spontaneously, AG must be negative. 

Heat of solution During the process of solvation, the solute must separate into particles. Solvent particles also must move apart in order to allow solute particles to come between them. Energy is required to overcome the attractive forces within the solute and within the solvent, so both steps are endothermic. When solute and solvent particles mix, the particles attract each other and energy is released. This step in the solvation process is exothermic. The overall energy change that occurs during the solution formation process is called the heat of solution. 

Polyurethane formation is a highly exothermic process. Polyurethane synthesis is a laboratory process which is mainly carried out by the solution polymerisation technique. The most common solvents used for this purpose... 

Dissolving soda ash is an exothermic process. Note that hydrate formation itself is also exothermic. This means that heat evolves even dining the addition of solid material to a slurry or saturated solution. 

The overall enthalpy change upon solution formation may be either positive or negative. Solution formation is favored both by a negative enthalpy change (exothermic process) and by a positive entropy change (the increase in disorder) of the system. 

The overall PES for nitration in the gas phase is very diffident fiom that in solution. In the gas phase, formation of the o-complex from the free reactants is a vay exothermic process with a zcto overall barrier. However, compared to solution, the deprotonation of the a-complex is a slower process. Different pathways for intramolecular proton transfo have been studied, including transfer to an oxygen as well as initial transfer to a nearby carbon [51,55,56]. We will not go into the details of these reactions, since they are of little relevance for solution chemistry. 

The overall solution-formation process is exothermic (Af/join < 0) when the heat given off in step 3 is greater than the sum of heat required for steps 1 and 2. The overall process is endothermic (A//soin > 0) when the heat given off in step 3 is less than the total required for steps 1 and 2. (Figure 13.3 depicts a solution formation that is endothermic overall.)... 

Solution formation may be endothermic or exothermic overall. An increase in entropy is the driving force for solution formation. Solute particles are surrounded by solvent molecules in a process called solvation. 

The military explosives RDX and HMX are manufactured from the 3 components using the Bachman process. Some of the possible mixtures may lead to fires in open vessels and explosions under confinement, and the exothermic and other effects (some calculated by the CHETAH program) for a wide range of mixtures are presented as ternary diagrams. It was also found that acetic anhydride layered onto solutions of ammonium nitrate in nitric acid exploded, owing to formation of acetyl nitrate. 

---