**13 and 14. Acids and Bases**
Introduction
Reactions with acids -
Practice some acid base simulations
When you click on this image a java file is downloaded - it may take a while (maybe even 120 seconds) depending on the speed of your internet link. Its well worth the wait.

http://phet.colorado.edu/en/simulation/acid-base-solutions

Acid-Base Solutions
Click to Run


Chapter 13: INTRODUCING ACIDS AND BASES (like vinegar and bicarb)
Acids are usually sour tasting, can change the colour of Indicators (dyes) and neutralize bases. Examples include Hydrochloric Acid, HCl - for cleaning bricks, Sulfuric Acid, H2SO4 - battery acid, Nitric Acid, HNO3 - dissolves Gold & Silver, Phosphoric Acid, H3PO4 - cleans jewellery and Ethanoic or Acetic Acid, CH3COOH - vinegar. Bases or Alkalis also change the colour of indicators and neutralize acids. Examples include Ammonia, NH3 - cleaners, Calcium Hydroxide, Ca(OH)2 - used in plaster and cement, Sodium Hydroxide, NaOH – drain/oven cleaners and Magnesium Hydroxide, Mg(OH)2 - used in aiding indigestion.
eg. Litmus and Universal Indicator (a mixture of indicators) turn in acid and purple in a base. Universal Indicator can produce different colours depending upon the concentration of the acid or base.
Reactions of Acids & Bases: Hint: Look for products: H2O or/& CO2, H2 or H2S, then determine other product a). Neutralisation Of Acids Or Bases: -

Acids will react with Bases to produce a neutral solution of an Ionic Salt and .

eg. HCl(aq) + NaOH(aq) --> NaCl(aq) + H2O(l).
Acid Base Salt Water

b). Reaction of Acids with Metals:

Acids react with certain Metals to produce a neutral solution of an Ionic Salt as well as releasing H2 gas.

eg. Mg(s) + 2 HCl(aq) --> MgCl2(aq) + H2(g). Only reactive metals (Group I, II & III) will react with acids.
Metal Acid Salt Hydrogen

c). Reaction of Acids with Metal Oxides:

Acids react with certain Metal Oxides to produce a neutral solution of an Ionic Salt and .

eg. CaO(s) + 2 HCl(aq) --> CaCl2(aq) + H2O(l). This is how oxide coatings are removed from structures.
Metal Oxide Acid Salt Water

d). Reaction of Acids with Metal Hydroxides:

Acids react with certain Metal Hydroxides to produce a neutral solution of an Ionic Salt and H2O.

eg. Ca(OH)2(aq) + 2 HCl(aq) --> CaCl2(aq) + 2 H2O(l). This can neutralise acidic soils and relieve
Metal Hydroxide Acid Salt Water stomach aches (antacids). e). Reaction of Acids with Metal Carbonates:
Acids react with Metal Carbonates to produce a neutral solution of an Ionic Salt, H2O and release CO2 gas.

eg. CaCO3(s) + 2 HCl(aq) --> CaCl2(aq) + H2O(l) + CO2(g). Calcium Carbonate is also called marble
Metal Carbonate Acid Salt Water Carbon Dioxide or _ & is used in statues.
Chemistry Unit 2 © 2003 Page 7 f). Reaction of Acids with Metal Bicarbonates (Hydrogen Carbonates):

Acids react with Metal Bicarbonates to produce a neutral solution of an Ionic Salt & H2O and release CO2 gas.

eg. Ca(HCO3)2(s) + 2 HCl(aq) --> CaCl2aq) + 2 H2O(l) + 2 CO2(g). In baking powders to make dough rise
Metal Bicarbonate Acid Salt Water Carbon Dioxide In antacids, relieve stomach aches.
g). Reaction of an Acidic Oxide with a Base:

Bases react with Acidic oxides (SO3, SO2, CO2, P4O10, NO2) to produce an Ionic salt and water.

eg. CO2(g) + Ca(OH)2(aq) --> CaCO3(s) + 2 H2O(l) SO3 & SO2 can produce acid rain
Acidic Oxide Base Salt Water NO2 can produce photochemical smog
h). Reaction of Acids with Metal Sulfides:

Acids react with some Metal Sulfides to produce a solution of an _ & release H2S gas. eg. FeS(s) + 2 HCl(aq) --> FeCl2(aq) + H2S(g). H2S gas smells like rotten eggs & is toxic.
Metal Sulfide Acid Salt Hydrogen Sulfide
i). Reaction of Acids with Metal Sulfites:

Acids react with some Metal Sulfites to produce a neutral solution of an Ionic Salt & H2O and release SO2 gas. eg. Na2SO3(s) + 2 HCl(aq) --> 2 NaCl(aq) + H2O(l) + SO2(g). Sulfur Dioxide gas is toxic but is
Metal Sulfite Acid Salt Water Sulfur Dioxide used as a preservative.
When writing Ionic Equations, include species that change state, don’t split (s), (l) & (g) but ignore Spectator Ions:
Part a/d): Part b): Part c): Part e/f): Part g): Part h): Part i):
H+(aq) + OH-(aq) --> H2O(l).

2 H+(aq) + Mg(s) --> Mg2+(aq) + _.

2 H+(aq) + CaO(s) --> Ca2+(aq) + H2O(l).

2 H+(aq) + CaCO3(s) or Ca(HCO3)2(s) --> Ca2+(aq) + CO2(g) + H2O(l) or Ca2+(aq) + 2 CO2(g) + 2 H2O(l). CO2(g) + Ca(OH)2(aq) --> H2O(l) + CaCO3(s).
p




FeS(s) + 2H+(aq) --> H2S(g) + Fe2+(aq). Note: Solids cannot be split into ions – only (aq) species can be split Na2SO3(s) + 2H+(aq) --> 2Na+(aq) + H2O(l) + SO2(g).


How to do a titration


http://www.dartmouth.edu/~chemlab/techniques/titration.html
http://www.dartmouth.edu/~chemlab/techniques/titration.html