Acid and Bases

Physical Properties Acid Taste sour Citric Acid and Ascorbic: lemons Carbonic and Phosphoric: carbonated beverages Acetic Acid: vinegar Conduct electricity Base Taste bitter Feel slippery: wet soap Conduct electricity

Chemical Properties Reactions Litmus paper Red = Acidic Blue = Basic Reactions Metals and Metal Carbonates Produce H 2 or CO 2 Geologists identify limestone with hydrochloric acid

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Ions Hydrogen Ion H + Sometimes H 3 O + Hydroxide OH - Hydrogen Bond Goes back and forth

Notice Exponent on 10 Is opposite of pH pH = - log [H+]

pOH = -log [OH - ] Think in terms of the base pOH [OH - ] 14 1 x x x 10 0 pH + pOH = 14

Water gains H+ Water loses H+

Neutralization Base + Acid  Salt + Water HCl(aq) + NaOH(aq)  NaCl(aq) + H 2 O(l) What type of compounds are each?

Acid Neutralizers Limestone Oceans and Acid Rain Calcium carbonate CCaO 3 Sometimes antacids can interfere with medications

Acid Base Reaction then Decomposition Why do some breads have holes? HC 2 H 3 O 2 (aq) + NaHCO 3 aq)  NaC 2 H 3 O 2 (aq) + H 2 CO 3 (aq) H 2 CO 3 (aq)  CO 2 (g) + H 2 O(l)

Practice Write the balanced equation for the reaction between zinc and nitric acid. Write the balanced equation for the reaction between magnesium carbonate and sulfuric acid.

Answers Zn(s) + 2HNO 3 (aq)  Zn(NO 3 ) 2 (aq) + H 2 (g) MgCO 3 (s) + H 2 SO 4 (aq)  MgSO 4 (aq) + H 2 O(l) + CO 2 (g) How do you know if you get hydrogen gas or carbon dioxide gas?

Practice Identify the base in the reaction. H 2 O(l) + CH 3 NH 2 (aq)  OH - (aq) +CH 3 NH 3 + (aq)

The base is CH 3 NH 2 (aq) The reactants have an acid and a base The products have conjugate pairs – match up (think Alg 2) There is an OH- ion in the products which is the conjugate (or pair) base What did the OH- start as? This is the acid (opposite of base) So, the other compound must be the base.

Practice Is the solution in which [H + ] = 1.0 x M acidic, basic or neutral? Is the solution in which [OH - ] = 1.0 x M acidic, basic or neutral?

Answers Is it H + or OH - ? H+ so low pH is more acidic, pH = 5, <7 so slightly acidic OH - so low pOH is basic, pOH = 11, >7 so strong acidic Or, think pH = 14 – pOH so pH = 3, strong acid

Practice – Neutralization Write the formula equation for the reactions between hydrioric acid and beryllium hydroxide. Write the formula equation for the reactions between perchloric acid and lithium hydroxide.

hydrioric acid and beryllium hydroxide Hyrd = hydrogen =H ioric = iodine = I Covalent bonding, share 1 e - Beryllium = Be is group 2 so 2 + Hydroxide = OH - is 1 - so need 2 Ionic bonding, metal and ion HI Be(OH) 2

perchloric acid and lithium hydroxide Chloric = Chlorine and Oxygen and acid so need Cl and O and H (need a list of common acids) Lithium = Li is group 1 so 1 + hydroxide = OH - so need 1 Ionic bonding, metal and ion LiOH HCIO 4

Answers 2HI(aq) + Be(OH) 2 (aq)  BeI(aq) + 2H 2 O(l) Think how many water? So balance the H HCIO 4 (aq) + LiOH(aq)  LiCIO 4 (aq) + H 2 O(l) Keep the ClO 4 as a unit even if it does not have ( )