Movie: types of chemical reactions:

Identify, give evidence for, predict products of, and classify the following types of chemical reactions: 1. Synthesis (Combination) 2. Decomposition 3. Single Replacement 4. Double Replacement 5. Neutralization (acid/base) 6. Combustion

 Synthesis  Decomposition  Neutralization  Single displacement  Double displacement  Combustion

A chemical change: any change in which a new substance is formed. Evidence of a Chemical Change:  Release of energy as heat (exothermic)  Release of energy as light  Change in colour  Formation of a gas  Change in odour…

1.Synthesis: A + B  AB 2.Decomposition: AB  A + B 3.Neutralization: Acid(H) + Base(OH)  Salt + H(OH) 4.Single displacement: A + BC  AC + B 5.Double displacement: AB + CD  AD + CB 6.Combustion: AB + oxygen  CO 2 + H 2 O

A + B  AB where A and B represent elements –The elements may form ionic compounds, like… –Sodium metal and chlorine gas combine to form sodium chloride. 2Na + Cl 2  2NaCl (c) McGraw Hill Ryerson 2007 See pages Sodium added to chlorine gas Synthesis reactions are also known as COMBINATION reactions. Two or more reactants (usually elements) join to form a compound.

Synthesis Reaction Example C + O 2 CO 2 OO C +  OO C General: A + B  AB

OTHER EXAMPLES… 1.Elements that form ionic compounds: Magnesium metal reacts with oxygen gas to form magnesium oxide. 2Mg + O 2  2MgO 2. Elements that form covalent compounds: Nitrogen gas and oxygen gas combine to form dinitrogen monoxide. 2N 2 + O 2  2N 2 O (c) McGraw Hill Ryerson 2007 SYNTHESIS REACTION (iron + sulphur):

Decomposition reactions are the opposite of synthesis reactions. –A compounds breaks down into two or more products (often elements). AB  A + B where A and B represent elements 1. Ionic compounds may decompose to produce elements, like the following: Table salt, sodium chloride, can be broken down into sodium metal and chlorine gas by melting salt at 800ºC and running electricity through it. 2NaCl  2Na + Cl 2 (c) McGraw Hill Ryerson 2007 See page 260

Types: Decomposition Example: NaCl General: AB  A + B  Cl Na Cl + Na

Types: Decomposition Example 2HgO  O Hg O OO + General: AB  A + B

2. Covalent compounds may decompose into elements, like the following: By running electricity through water, the water molecules decompose into hydrogen and oxygen gases. 2H 2 O  2H 2 + O 2 (c) McGraw Hill Ryerson 2007 DECOMPOSITION REACTION: tch?v=hWiWjWHdHXM

Single replacement reactions replace one element from a compound with another element. –A compound and an element react, and the element switches places with part of the original compound. A + BC  B + AC where A is a metal, or A + BC  C + BA where A is a non-metal (c) McGraw Hill Ryerson 2007 See page 261

Types: Single replacement Example: Zn + CuCl 2  Zn Cl Cu + General: AB + C  AC + B Cl Zn Cu +

1. When A is a metal: Aluminum foil in a solution of copper(II) chloride produces solid copper and aluminum chloride. 2Al + 3CuCl 2  3Cu + 2AlCl 3 2. When A is a non-metal: When fluorine is bubbled through a sodium iodide solution, iodine and sodium fluoride are produced. Fl 2 + 2NaI  I 2 + 2NaF SINGLE REPLACEMENT:

Double replacement reactions swap elements between 2 compounds that react together to form two new compounds. –Two compounds react, with elements switching places between the original compounds. AB + CD  AD + CB (c) McGraw Hill Ryerson 2007 See page 262

Types: Double replacement Example: MgO + CaS AB + CD  AD + CB S O  Mg Ca + O S Mg Ca +

–When potassium chromate and silver nitrate react, they form a red precipitate, silver chromate, in a solution of potassium nitrate. –K 2 CrO 4 + 2AgNO 3  Ag 2 CrO 4 + 2KNO 3 (c) McGraw Hill Ryerson 2007 silver chromate Two solutions react to form a precipitate (solid) and another solution. Ionic solution + ionic solution  ionic solution + ionic solid. AB + CD  AD + CB DOUBLE REPLACEMENT:

Neutralization reactions occur when an acid (most compounds starting with H) and a base (most compounds ending in OH) react to form a salt and water. Neutralization reactions are a type of double replacement. Acid + base  salt + water HOH HX + MOH  MX + H 2 O where X and M are elements (c) McGraw Hill Ryerson 2007 See page 263

1. Sulfuric acid is used to neutralize calcium hydroxide: H 2 SO 4 + Ca(OH) 2  CaSO 4 + 2H 2 O 2. Phosphoric acid helps to neutralize the compounds that cause rust, such as iron(II) hydroxide. H 3 PO 4 + 3Fe(OH) 2  Fe 3 (PO 4 ) 2 + 6H 2 O (c) McGraw Hill Ryerson 2007 See page 263 NEUTRALIZATION:

Combustion reactions occur when a compound or element react with oxygen to release energy and produce an oxide. –Also sometimes referred to as hydrocarbon combustion. C X H Y + O 2  CO 2 + H 2 O where X and Y represent integers (c) McGraw Hill Ryerson 2007 See page 264 METHANOL + oxygen:

1. Natural gas (methane) is burned in furnaces to heat homes. CH 4 + O 2  CO 2 + 2H 2 O + energy 2. An acetylene torch is used to weld metals together. 2C 2 H 2 + 5O 2  4CO 2 + 2H 2 O + energy 3. Carbohydrates like glucose combine with oxygen in our body to release energy. C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy (c) McGraw Hill Ryerson 2007 Acetylene torch

(c) McGraw Hill Ryerson Movie of five of the main reactions