Dissolving and the Forces of Attraction

Dissolving is what kind of change

Is a physical Change

How are MOLECULES OR IONs of a solid solute held together

Held together by BONDS

What occurs to these bonds in dissolving

These bonds BREAK and the IONS or MOLECULES of the solute become ATTRACTED TO THE SOLVENT PARTICLES

How many Processes are in dissolving

3

1. Bonds BROKEN between molecules or ions of a SOLUTE

Always ENDOTHERMIC ( requires energy )

2. Bonds BROKEN between molecules of a SOLVENT

Always ENDOTHERMIC

3. Bonds FORM between molecules of SOLVENT and SOLUTE

Always EXOTHERMIC

Energy change in dissolving is equal to

The SUM of the three steps ( law of conservation of energy )

If more ENERGY is RELEASED then is REQUIRED the overall dissolving process is

EXOTHERMIC

If LESS ENERGY is RELEASED then is REQUIRED the overall process is

ENDOTHERMIC