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Types of Chemical Reactions. Movie: types of chemical reactions: http://www.youtube.com/watch?v=i-HHvx1VC_8. Learning Outcomes. Identify, give evidence for, predict products of, and classify the following types of chemical reactions: 1. Synthesis (combination) 2. Decomposition
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Types of Chemical Reactions Movie: types of chemical reactions: http://www.youtube.com/watch?v=i-HHvx1VC_8
Learning Outcomes 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
Vocabulary • Synthesis • Decomposition • Neutralization • Single displacement • Double displacement • Combustion
Chemical Reactions • A chemical change: any change in which a new substance is formed. • Evidence of a Chemical Change: • Release of energy as heat • Release of energy as light • Change in color • Formation of a gas • Formation of a precipitate (solid) • Change in odor…
Types of Chemical Reactions Neutralization: Acid(H) + Base(OH) salt + H(OH) Combustion: AB + oxygen CO2 + H2O Synthesis: A + B AB Decomposition: AB A + B Single displacement: A + BC AC + B Double displacement: AB + CD AD + CB
Synthesis Reactions • Synthesis reactions are also known as FORMATION reactions. • Two or more reactants (usually elements) join to form a compound. • 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 + Cl2 2NaCl Sodium added to chlorine gas
C C C C C C C C C C C C C C C C + O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O Types: Synthesis Example C + O2 General: A + B AB
Synthesis Reactions OTHER EXAMPLES… • Elements that form ionic compounds: Magnesium metal reacts with oxygen gas to form magnesium oxide. • 2Mg + O2 2MgO 2. Elements that form covalent compounds: Nitrogen gas and oxygen gas join to form dinitrogen monoxide. • 2N2 + O2 2N2O SYNTHESIS REACTION (iron + sulphur): http://www.youtube.com/watch?v=A5H6DVe5FAI See pages 258 - 259 (c) McGraw Hill Ryerson 2007
Decomposition Reactions • 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 + Cl2
Decomposition Reactions See page 260 (c) McGraw Hill Ryerson 2007
+ Na Na Cl Cl Types: Decomposition Example: NaCl Demo Example: H2O2(hydrogen peroxide) 2H2O2 2H2O + O2 General: AB A + B
Hg Hg Hg Hg + O O O O Types: Decomposition Example 2HgO General: AB A + B
Decomposition Reactions 2. Covalent compounds may decompose into elements, like the following: • By running electricity through water, the water molecules decompose into hydrogen and oxygen gases. • 2H2O 2H2 + O2 DECOMPOSITION REACTION: http://www.youtube.com/watch?v=NddwtXEA_Ak See page 260 (c) McGraw Hill Ryerson 2007
Single Replacement Reactions • 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 See page 261 (c) McGraw Hill Ryerson 2007
+ + Cl Cl Cl Cl Zn Zn Cu Cu Types: Single displacement Example: Zn + CuCl2 General: A+ BC AC + B
Example: Single displacement Example: 2Na + 2H2O 2NaOH + H2 HOH Observe what happens General: A+ BC AC + B
Single Replacement Reactions 1. When A is a metal: • Aluminum foil in a solution of copper(II) chloride produces solid copper and aluminum chloride. (We did this in class) • 2Al + 3CuCl2 3Cu + 2AlCl3 2. When A is a non-metal: • When fluorine is bubbled through a sodium iodide solution, iodine and sodium fluoride are produced. • Fl2 + 2NaI I2 + 2NaF SINGLE REPLACEMENT: http://www.youtube.com/watch?v=hKtynbVtMKc
Double Replacement Reactions • 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 See page 262 (c) McGraw Hill Ryerson 2007
Double Replacement Reactions See page 262 (c) McGraw Hill Ryerson 2007
Ca Ca + + Mg Mg S S O O Types: Double displacement Example: MgO + CaS General: AB + CD AD + CB
Double Replacement Reactions • Two solutions react to form a precipitate (solid) and another solution. • Ionic solution + ionic solution ionic solution + ionic solid. AB + CD AD + CB • When potassium iodide and lead (II) nitrate react, they form a yellow precipitate, lead (II) iodide, in a solution of potassium nitrate. • 2KI + Pb(NO3)2 PbI2 + 2KNO3 DOUBLE REPLACEMENT: http://www.youtube.com/watch?v=opY3FLrPTa4 (c) McGraw Hill Ryerson 2007
Neutralization Reactions • 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 HX + MOH MX + H2O where X and M are elements See page 263 (c) McGraw Hill Ryerson 2007
Neutralization Reactions 1. Sulfuric acid is used to neutralize calcium hydroxide: • H2SO4 + Ca(OH) 2 CaSO4 + 2H2O 2. Phosphoric acid helps to neutralize the compounds that cause rust, such as iron(II) hydroxide. • H3PO4 + 3Fe(OH)2 Fe3(PO4)2 + 6H2O NEUTRALIZATION: http://www.youtube.com/watch?v=_P5hGzA6Vb0 See page 263 (c) McGraw Hill Ryerson 2007
Combustion Reactions • 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. CXHY + O2 CO2 + H2O where X and Y represent integers METHANOL + oxygen: http://www.youtube.com/watch?v=98JuJ-G1qXY&feature=related See page 264 (c) McGraw Hill Ryerson 2007
Combustion Reactions 1. Natural gas (methane) is burned in furnaces to heat homes. • CH4 + O2 CO2 + 2H2O + energy 2. An acetylene torch is used to weld metals together. • 2C2H2 + 5O2 4CO2 + 2H2O + energy 3. Carbohydrates like glucose combine with oxygen in our body to release energy. • C6H12O6 + 6O2 6CO2 + 6H2O + energy Acetylene torch See page 264 (c) McGraw Hill Ryerson 2007
SUMMARY OF REACTIONS MOVIE TO REVIEW: http://www.bcscience.com/bc10/pgs/videos_013_chemical_reactions.html See page 265 Take the Section 6.1 Quiz (c) McGraw Hill Ryerson 2007