chapter 5 -enthalpy changes in solution

what is the standard enthalpy change of solution?

• the enthalpy change that takes place when 1 mole of a solute dissolves in a solvent

• the standard enthalpy change of solution can be endo or exothermic

  • if the solvent is water, the ions from the ionic lattice finish up surrounded with water molecules as aqueous ions

equation for enthalpy change of solution of sodium chloride in water?

what 2 processes occur when a solid ionic compound dissolves in water?

• the ionic lattice breaks up

• water molecules are attracted to, and surround, the ions

what happens when the ionic lattice is broken up?

• it forms separate gaseous ions

  • this is the opposite energy change from lattice energy, which forms the ionic lattice from gaseous ions

• the separate gaseous ions interact with polar water molecules to form hydrated aqueous ions

• the energy change involved is called the enthalpy change of hydration

what do energy cycles look like for enthalpy of hydration and solution?