13+and+14.+Acids+and+Bases

**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. media type="custom" key="10181451" http://phet.colorado.edu/en/simulation/acid-base-solutions

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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, H 2 SO 4 - battery acid, Nitric Acid, HNO 3 - dissolves Gold & Silver, Phosphoric Acid, H 3 PO 4 - cleans jewellery and Ethanoic or Acetic Acid, CH 3 COOH - vinegar. Bases or Alkalis also change the colour of indicators and neutralize acids. Examples include Ammonia, NH 3 - 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: H 2 O or/& CO 2, H 2 or H 2 S, 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) + H 2 O(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 H 2 gas.

eg. Mg(s) + 2 HCl(aq) --> MgCl 2 (aq) + H 2 (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) --> CaCl 2 (aq) + H 2 O(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 H 2 O.

eg. Ca(OH) 2 (aq) + 2 HCl(aq) --> CaCl 2 (aq) + 2 H 2 O(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, H 2 O and release CO 2 gas.

eg. CaCO 3 (s) + 2 HCl(aq) --> CaCl 2 (aq) + H 2 O(l) + CO 2 (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 & H 2 O and release CO 2 gas.

eg. Ca(HCO 3 ) 2 (s) + 2 HCl(aq) --> CaCl 2 aq) + 2 H 2 O(l) + 2 CO 2 (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 (SO 3, SO 2 , CO 2 , P 4 O 10 , NO 2 ) to produce an Ionic salt and water.

eg. CO 2 (g) + Ca(OH) 2 (aq) --> CaCO 3 (s) + 2 H 2 O(l) SO 3 & SO 2 can produce acid rain Acidic Oxide Base Salt Water NO 2 can produce photochemical smog h). Reaction of Acids with Metal Sulfides:

Acids react with some Metal Sulfides to produce a solution of an _ & release H 2 S gas. eg. FeS(s) + 2 HCl(aq) --> FeCl 2 (aq) + H 2 S(g). H 2 S 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 & H 2 O and release SO 2 gas. eg. Na 2 SO 3 (s) + 2 HCl(aq) --> 2 NaCl(aq) + H 2 O(l) + SO 2 (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) --> H 2 O(l).

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

2 H + (aq) + CaO(s) --> Ca 2+ (aq ) + H 2 O(l).

2 H + (aq) + CaCO 3 (s) or Ca(HCO 3 ) 2 (s) --> Ca 2+ (aq) + CO 2 (g) + H 2 O(l) or Ca 2+ (aq) + 2 CO 2 (g) + 2 H 2 O(l). CO 2 (g) + Ca(OH) 2 (aq) --> H 2 O(l) + CaCO 3 (s). p

FeS(s) + 2H + (aq) --> H 2 S(g) + Fe 2+ (aq). Note: Solids cannot be split into ions – only (aq) species can be split Na 2 SO 3 (s) + 2H + (aq) --> 2Na + (aq) + H 2 O(l) + SO 2 (g).

How to do a titration

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