types of chemical reactions. watch these reactions!
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Watch These Reactions!TRANSCRIPT
Types of Chemical Reactions
Watch These Reactions!
Combination Reactions• a chemical change in which two or more
substances react to form a single new substance
• the general form is A + X AX– 2Cu(s) + S(s) Cu2S(s)– 2Fe(s) + 3S(s) Fe2S3(s)– K(s) + Cl2(g) ?
• ions are: K+1 and Cl-1
• therefore: K(s) + Cl2(g) KCl(s)• balanced: 2K(s) + Cl2(g) 2KCl(s)
Decomposition Reactions• a chemical change in which a single
compound breaks down into two or more simple products.
• the general form is AX A + X– 2HgO(s) → 2Hg(l) + O2(g)– Zn(ClO3)2 ZnCl2 + 3O2
– H2O(l) → ?• H2O(l) → H2(g) + O2(g)• 2H2O(l) → 2H2(g) + O2(g)
electricity
electricity
electricity
Single Replacement Reactions• a chemical change in which one element
replaces a second element in a compound– metal will replace a metal, or a
nonmetal will replace a nonmetal – general form is A + BX AX + B
– Zn (s) + 2HCl (aq) ZnCl2 (aq) + H2 (g)
– Ni + AgNO3 ?• nickel replaces the metallic ion Ag+1.• silver becomes free silver and the
nickel becomes the nickel(II) ion (Ni+2)• NO3 is 1-
• Ni + AgNO3 Ag + Ni(NO3)2
–balance the equation:–Ni + 2AgNO3 2Ag + Ni(NO3)
• Al + Fe2O3 ?– O is 2- and therefore Fe was 3+
– aluminum will replace iron(III)– iron(III) becomes Fe and aluminum metal
becomes Al3+
– Al + Fe2O3 Fe + Al2O3
– 2Al + Fe2O3 2Fe + Al2O3
• Cl2 +2 NaI ?– Cl2 +2NaI 2 NaCl + I2
Double Replacement Reactions
• an exchange of positive ions between two chemicals
• general form is AX + BY BX + AY• CuSO4 + Na2CO3 Na2SO4 + CuCO3
• NaOH + CuSO4 ?• The Na+ and Cu2+ switch places.• Na+ combines with SO4
2- to form Na2SO4.
• Cu2+ combines with OH- to form Cu(OH)2
• NaOH + CuSO4 Na2SO4 + Cu(OH)2
• 2NaOH + CuSO4 Na2SO4 + Cu(OH)2
• Na2CO3 + HCl ?• Na+1 combines with Cl-1 to form
NaCl• H+ combines with CO3
2- to form H2CO3
• Na2CO3 + 2HCl 2NaCl + H2CO3
Combustion Reaction• a type of combination reaction
where a substance reacts with oxygen
• often the burning of a fuel that produces carbon dioxide, water, light, and heat
• CH4 + O2 ?• CH4 + O2 CO2 + H2O• CH4 + 2O2 CO2 + 2H2O
Practice• Classify each of the following as to type:
• H2 + Cl2 2HCl– combination
• Ca + 2H2O Ca(OH)2 + H2
– single replacement
Practice• 2CO + O2 2CO2
– combination and combustion
• 2KClO3 2KCl + 3O2
– decomposition
Practice• FeS + 2HCl FeCl2 + H2S
– double replacement
• Zn + HCl ?– single replacement– Zn + 2HCl ZnCl2 + H2