Tag: Chemistry

Change in Enthalpy

Change in Enthalpy

Change in Enthalpy

12/04/16

“How can we measure the change of energy in a thermodynamic system when the system itself changes?”

 

All thermodynamic systems have the summation of the parts of their energy represented by enthalpy. However, the universe is almost never in a static state, and is always changing. Consequently, all thermodynamic systems will be in perpetual change as well. And it turns out that this change in enthalpy has very practical results for scientific use. A change in enthalpy can be quantitatively described by taking the difference of the enthalpy of the system after the change and before the change. If the  enthalpy has gone up, then that means that energy must have been added to the system, making it an endothermic process. If the enthalpy has gone down, then heat was removed from the system and it was an exothermic process. The change in Enthalpy is often symbolically represented using a (delta)H

Ion-dipole forces

Ion-dipole forces

Ion-dipole forces

11/27/16

“What exactly causes ionic compounds to be dissolved in dipole solvents?”

 

One of the first facts one will learn in a Chemistry course is that ionic compounds such as salt (NaCl) will dissolve in dipolar solvents. However, have you ever wondered why does this phenomena take place? Well, as scientifically minded people, we should explore anything that we don’t know. Ionic compounds are held together by ionic bonds, which are the result of two or more atoms sharing electrons. And since these ionic bonds depend upon factors of charge distribution, they susceptible to the influence of external electric forces. As such, if they come into close contact to polar substances such as dipole solvents, the resulting ion-dipole force would rip apart the compounds.