11/13 Notes Conductivity of solutions A. In order for a solution to conduct electricity it must be made up of ions (charged particles) often times when things dissolve they break down into their ions, this is called dissociation. B.If a solution can conduct electricity it is known as an electrolyte and if it can not it is known as a non-electrolyte

11/13 Notes There are three steps to forming a solution A.First step the solute molecules are drawn apart from each other by the solvent (Dissociation) B.Second the solvent molecules make room for the solute molecules to fit between the solvent molecules C.Third the solvent molecules and solute molecules form a weak bond to hold them suspended in space (Hydrogen Bonding)

11/13 Notes Special Properties of solutions Freezing pt. Depression – solutions have lower freezing points than the original solvent. Ex. Salt on roads in winter. This makes water freeze at –10 to –20 degrees instead of 0 Boiling Point elevation – A solution has a higher boiling point than the original solvent.

11/13 Notes Acids and Bases pH Scale (measure of free hydrogen ions in solution) The more free hydrogen the more acidic it is.

11/13 Notes pH Scale is a log scale (bases of 10) so something with a pH of 6 is 10 times more acidic than pH 7. pH 3 is 10000 times more acidic than pH 7

11/13 Notes Acids – sometimes called Hydrogen (H) donors. They give up hydrogen ions when dissolved in water. Form Hydronium ions H3O+. pH below 7. You can identify acids because they generally start with Hydrogen. Ex. HNO3, H2SO4, HCl Acids generally taste sour, turn litmus paper red

11/13 Notes Bases – Proton acceptors or Hydrogen acceptors. pH above 7. Contain the hydroxide group OH-. Thus they want to accept hydrogen to make water. Ex. NaOH, Ca(OH)2, KOH Bases make good cleaners, slippery, taste bitter, turn litmus paper blue

11/13 Notes Indicator – Substance that changes color in the presence of an acid or base. Many types that work at a variety of pH’s. Tell whether you have an acid or base and how strong.

11/13 Notes Neutralization Rxn When you react an acid with a base you have a neutralization reaction occur. They counter act each other to make pH neutral. The product of this reaction is a salt and water. Example HCl + NaOH  H20 + NaCl This is basically a double replacement reaction.