Neutralization ReactionsNeutralization Reactions  Type of acid-base reaction  Strong Acid + Strong Base----all OH - ions combine with H + ions to give water molecules  Produce water and a SALT, MX. A salt is an ionic compound. HX + MOH  MX + H 2 O ACID + BASE  SALT + WATER

Example 1:Example 1: NaOH (aq) + HCl (aq)  NaCl (aq) + H 2 O (l)  What are the spectator ions?  What is the net ionic equation?

Example 1: continuedExample 1: continued NaOH (aq) + HCl (aq)  NaCl (aq) + H 2 O (l) Na + (aq) + OH - (aq) + H + (aq) + Cl - (aq)  Na + (aq) + Cl - (aq) + H 2 O (l)  What are the spectator ions? Na + and Cl -  What is the net ionic equation? OH - (aq) + H + (aq)  H 2 O(liq)----always with strong acids and bases

Salts  Ionic compounds  Formed using cation from base and anion of acid  Can have acidic or basic properties if one acid/base component is strong and the other is weak.  Examples: NaCl, Na 2 SO 4, MgCl 2

Example 2:Example 2:  Predict the products from the acid-base reaction between H 2 CO 3 + Sr(OH) 2  Write the complete, balanced equation as well as the net-ionic equation.

Practice! Complete and balance the following acid-base reactions. Write the net-ionic equation as well: 1)HClO 4 + NaOH  2) HBr + Ba(OH) 2  3) HNO 3 + KOH  4) Ca(OH) 2 + HNO 3  5) Mg(OH) 2 + HCl 

What are acid-base indicators?  Contains a weak acid and its conjugate base  Weak acid—one color  Conjugate base—different color  Changes color based on what solution (acidic or basic) it is placed in.  Change color over a specific pH range – transition interval  Used when specific pH measurements not needed, seen a lot with titrations

Common IndicatorsCommon Indicators  Phenolphthalein  Litmus indicator  Broad pH range  Litmus—  Dye originating from lichens  pH 8.3 (blue)

Buffers  A mixture composed of a weak acid and its conjugate base OR weak base and its conjugate acid  buffers” or reduces the affect of a change in the pH of a solution  Absorbs slight changes in pH resulting from the addition of small acid/base amounts to water.  Buffer capacity—  indicates how much strong acid/base can be tolerated in a buffer solution before pH changes  Trait of buffer

1)Acidic Buffers  Formed from mixing a weak acid and its conjugate base  pH < 7 2)Basic Buffers  Formed from mixing a weak base and its conjugate acid  pH > 7 Types of buffersTypes of buffers

Why are buffers important to us?  Buffers present in our body keep fluids within a certain pH range.  Blood has a pH range of approximately  A buffer involving H 2 CO 3 /HCO 3 - maintains the blood pH

Homework:  p. 524 # 20, 31 (a and b), 33 (a and b), 34