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PAP CHEMISTRY. Pick up the PPT notes and the practice paper off the front demo table. . ACIDS AND BASES. PAP Chem Chapter 1: Intro to Chem. www.lab-initio.com. electrolytes electrolytes. Properties. ACIDS. BASES. bitter taste. sour taste. turn litmus red. turn litmus blue.
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PAP CHEMISTRY Pick up the PPT notes and the practice paper off the front demo table.
ACIDSAND BASES PAP Chem Chapter 1: Intro to Chem www.lab-initio.com
electrolytes electrolytes Properties ACIDS BASES • bitter taste • sour taste • turn litmus red • turn litmus blue • react with metals to form H2 gas • slippery feel • vinegar, milk, soda, apples, citrus fruits • ammonia, lye, antacid, baking soda ChemASAP
Acids are Proton(H+ion)Donors Strong acids are assumed to be 100% ionized in solution (goodH+donors). HCl HNO3 H2SO4 Weak acids are usually less than 5% ionized in solution (poorH+donors). Organic acids H3PO4 HC2H3O2
- + Strength • Strong Acid/Base • 100% ionized in water • strong electrolyte HCl HNO3 H2SO4 HBr HI HClO4 NaOH KOH Ca(OH)2 Ba(OH)2
- + Strength • Weak Acid/Base • does not ionize completely • weak electrolyte HF CH3COOH H3PO4 H2CO3 HCN NH3
Acids Taste Sour Citric acid in citrus fruit Malic acid in sour apples Lactic acid in sour milk and sore muscles Butyric acid in rancid butter Organic acids are weak acids. Some are used as flavoring agents in food.
Acids Effect Indicators Blue litmus paper turns red in contact with an acid. Methyl orange turns red with addition of an acid
Acids React with Active Metals Acids react with active metals to form salts and hydrogen gas. Mg + 2HCl MgCl2 + H2(g) Zn + 2HCl ZnCl2 + H2(g) Mg + H2SO4 MgSO4 + H2(g)
AcidsReact withCarbonates 2HC2H3O2 + Na2CO3 2 NaC2H3O2 + H2O + CO2
Effects of Acid Rain on Marble(calcium carbonate) George Washington: BEFORE George Washington: AFTER
Acids Neutralize Bases Neutralization reactions ALWAYS produce asalt and water. OH- (hydroxide) in base combines with H+ in acids to form water H++OH-H2O HCl + NaOHNaCl+H2O H2SO4 + 2NaOH Na2SO4+2H2O 2HNO3 + Mg(OH)2Mg(NO3)2+2H2O
H H – + O O Cl Cl H H H H Definitions • Arrhenius - In aqueous solution… • Acidsform hydronium ions (H3O+) HCl+ H2O H3O+ + Cl– acid
H H – + N O O N H H H H H H H H Definitions • Arrhenius - In aqueous solution… • Bases form hydroxide ions (OH-) NH3+ H2O NH4+ + OH- base
conjugate base conjugate acid Definitions • Brønsted-Lowry • Acidsare proton (H+) donors. • Bases are proton (H+) acceptors. HCl + H2O Cl– + H3O+ acid base
Definitions H2O + HNO3 H3O+ + NO3– B A CA CB
Definitions NH3 + H2O NH4+ + OH- B A CA CB • Amphoteric - can be an acid or a base.
F - H2PO4- H2O HF H3PO4 H3O+ Definitions • Give the conjugate base for each of the following: • (these are acids) • Polyprotic - an acid with more than one H+
Br - HSO4- CO32- HBr H2SO4 HCO3- Definitions • Give the conjugate acid for each of the following: • (these are bases-accept protons)
Definitions • Lewis • Acidsare electron pair acceptors. • Bases are electron pair donors. Lewis base Lewis acid
Acid Nomenclature • HBr • H2CO3 • H2SO3 hydrobromic acid • 2 elements, -ide • 3 elements, -ate carbonic acid sulfurous acid • 3 elements, -ite
Acid Nomenclature • hydrofluoric acid • sulfuric acid • nitrous acid • 2 elements H+ F- HF • 3 elements, -ic H+ SO42- H2SO4 H+ NO2- HNO2 • 3 elements, -ous
Properties of Bases • Bases are proton (hydrogen ion, H+) acceptors • Bases have a pH greater than 7 • Bases taste bitter • Bases effect indicators • Red litmus turns blue • Phenolphthalein turns purple • Solutions of bases feel slippery • Bases neutralize acids
Bases are Proton (H+ ion) Acceptors Sodium hydroxide (lye),NaOH Potassium hydroxide, KOH Magnesium hydroxide,Mg(OH)2 Calcium hydroxide (lime),Ca(OH)2
Bases Effect Indicators Redlitmus paper turnsbluein contact with a base. Phenolphthalein turnsbright pinkin a base.
Bases Neutralize Acids Milk of Magnesia contains magnesium hydroxide,Mg(OH)2,which neutralizes stomach acid,HCl. 2 HCl + Mg(OH)2 MgCl2 + 2 H2O