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Reactions. Reaction Types. Single-replacement One element replaces a second element in a compound Cl 2 + 2 NaBr 2 NaCl + Br 2 Zn + H 2 SO 4 ZnSO 4 + H 2 Refer to Table 11.2 on page 333. Reaction Types ( cont ). Decomposition
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Reaction Types • Single-replacement • One element replaces a second element in a compound • Cl2 + 2 NaBr 2 NaCl + Br2 • Zn + H2SO4 ZnSO4 + H2 • Refer to Table 11.2 on page 333
Reaction Types (cont) • Decomposition • Single compound breaks down into 2 or more simpler compounds • 2 H2O 2 H2 + O2 • CaCO3 CaO + CO2
Reaction Types (cont) • Combination • 2 or more reactants form a single new substance • Fe + S FeS • 2CaO + 2 H2O 2 Ca(OH)2
Practice • Complete the worksheet in groups. • Have the first 5 equations completed by the end of class.
Reaction Types (cont) • Double-replacement • Positive ions are exchanged between two compounds • Generally occur in aqueous solution and produce a precipitate • AgNO3 + NaCl AgCl + NaNO3 • 2 NaOH + H2SO4 Na2SO4 + 2 H2O
Reaction Types (cont) • Combustion • Element, or compound, reacts with oxygen, producing heat • Oxygen always involved as reactant • CH4 + 2 O2 CO2 + 2 H2O • C2H5OH + 3 O2 2 CO2 + 3 H2O
Example • Bike Manufacturing • Frame + wheel + handlebar + pedal = bicycle • Identify the components, how many are needed? • 1 frame, 2 wheels, 1 handlebar and 2 pedals • Skeleton equation: • F + W + H + P = FW2HP2 • Balanced? • F + 2 W + H + 2 P = FW2HP2 • http://youtu.be/QjVYz00-Kxc
Example • Equation IS balanced:
Process • Write the skeleton equation first • Use coefficients to balance the equation • Law of Conservation of Mass • Mass is conserved • Atoms in products are the same as the reactants, but rearranged
Practice • Zn + HCl ZnCl2 + H2 • Zn + 2 HCl ZnCl2 + H2 • C2H6 + O2 CO2 + H2O • 2C2H6+ 7 O2 4CO2 + 6 H2O
BCE Practice • ___ Al2O3 ___ Al + ___ O2 • ___ BaCl + ___ H2SO4 ___ BaSO + ___ HCl • ___ CuCl2 + H2S ___ CuS + ___ HCl
Summary • What is a coefficient? • What are the on the left of the chemical equation? On the right? • Worksheet due tomorrow!!