Predicting Reaction Products

Free Response Section of the AP Chemistry Exam Question 4: (10 % of Section Score) 3 Reaction Predictions - Must give a balanced chemical equation - Must write the equation in net ionic form - Must answer one question about the reaction

Successfully Predicting Reaction Products Know the list of Common Ions Knowledge of Nomenclature Know how to use SRP Table Learn the Solubility Rules Know the Reaction Classifications Write net ionic equations

Classification of Reactions Acid/Base Precipitation Hydrolysis Decomposition (& reversed) Ligands REDOX Organic

Acid/Base Reactions HX + MOH ----> MX + HOH

Acid/Base Reaction Sample # (c) equal volumes of 0.1-molar sulfuric acid and 0.1-molar potassium hydroxide are mixed.

Acid/Base Sample # (d) Equal volumes of equimolar solutions of phosphoric acid and potassium hydroxide are mixed.

Precipitation Reactions One or more products is(are) not significantly soluble in water. CuSO 4 and BaOH  Generally both reactants are salts in solution AX + BY -----> AY + BX Where AY and/or BX is (are) insoluble in water Net ionic equation: A + + Y > AY Where AY is insoluble in water & BX is soluble in water

Precipitation Reactions Sample #1 2003B (d) A solution of lead(II) nitrate is added to a solution of potassium sulfate.

Precipitation Reactions Sample # (a) A solution of sodium iodide is added to a solution of lead(II) acetate.

Hydrolysis Reactions Generally three types: – A metal oxide reacts with water to form a base. – A nonmetal oxide reacts with water to form an acid. – A metal hydride reacts with water to form a base & hydrogen gas.

Hydrolysis Reaction Sample # (c) Solid cesium oxide is added to water.

Hydrolysis Reaction Sample # (h) solid dinitrogen pentoxide is added to water.

Hydrolysis Reaction Sample # (g) Solid calcium hydride is added to distilled water.

Decomposition Reactions A lone compound is strongly heated, exposed to strong sunlight or electric current.

Decomposition Reactions Compounds that readily decompose: – Metallic carbonates – Most metallic hydroxides – Metallic chlorates – Metallic sulfites – Some acids – Peroxides – Electrolysis of salts

Decomposition Reaction Sample # (a) Solid calcium carbonate is strongly heated.

Decomposition Reaction Sample #2 Solid calcium hydroxide is strongly heated.

Decomposition Reaction Sample #3 Solid potassium chlorate is strongly heated.

Decomposition Reaction Sample # (e) Solid calcium sulfite is heated in a vacuum.

Decomposition Reaction Sample #5

Decomposition Reaction Sample #6

Decomposition Reaction Sample #7

Decomposition Reaction Sample #8 Molten magnesium bromide is electrolyzed using inert electrodes.

Ligand Reactions Ligand reactions involve the reaction between ligands and some metal anions (Fe, Cu, Pb, Ag, Au, Sn, Pt, Co, etc). Learn the common ligands: CN -, SCN -, NO 2 -, NH 3, H 2 O, OH -, halides (F -, Cl -, Br -, I - )

Ligand Reactions General rule: The number of ligands attached to the metallic anion is usually DOUBLE the cation’s charge. Ag + → Ag(NH 3 ) 2 + Cu 2+ → Cu(NH 3 ) 4 2+ Fe 3+ → Fe(NH 3 ) 6 3+

Ligand Reactions Sample # (e) Excess concentrated aqueous ammonia is added to solid silver chloride.

Ligand Reactions Sample # (f) A solution of ammonium thiocyanate is added to a solution of iron(III) chloride.

REDOX Reactions These are reactions that involve CHANGES in oxidation state. Learn the list of important oxidizers and reducers from the handout.

REDOX Reactions Sample # (f) Magnesium ribbon is burned in oxygen.

REDOX Reactions Sample # (g) A bar of strontium metal is immersed in a 0.1 M copper(II) nitrate solution.

REDOX Reactions Sample # (f) Chlorine gas is bubbled through a solution of potassium bromide.

REDOX Reactions Sample # (g) Acidified solutions of potassium permanganate and iron(II) nitrate are mixed together.

REDOX Reactions Sample # (e) A solution of iron(II) chloride is added to an acidified solution of sodium dichromate.

REDOX Reactions Sample # (a) A strip of copper is immersed in dilute nitric acid

Organic Reactions Reactions involving compounds containing hydrogen, carbon, and sometimes other nonmetal elements. Learn the hydrocarbon nomenclature and common functional groups.

Organic Reactions Sample #1 2003B (c) Propanone is burned in air

Organic Reactions Sample # (e) Methane gas is heated with an excess of chlorine gas.

Organic Reactions Sample # (g) ethene (ethylene) gas is bubbled through a solution of bromine.

Organic Reactions Sample # (c) Ethanol and formic acid (methanoic acid) are mixed and warmed.