Before revision: It is thus the opposite of a synthesis reaction and can be written as AB->A + B One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen gas: 2H2O->2H2 + O2 Single displacement In a single displacement reaction, a single uncombined element replaces another in a compound; in other words, one element trades places with another element in a compound These reactions come in the general form of: A + BC->AC + B One example of a single displacement reaction is when magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas: Mg + 2H2O->Mg(OH)2 (v) + H2 (^) Double displacement In a double displacement reaction, the anions and cations of two compounds switch places and form two entirely different compounds.
After revision: solidIt is thus the opposite of a synthesis reaction and can be written as AB->A + B One example of a decomposition reaction is the electrolysis of water to make oxygen and hydrogen gas: 2H2O->2H2 + O2 Single displacement In a single displacement reaction, a single uncombined element replaces another in a compound; in other words, one element trades places with another element in a compound These reactions come in the general form of: A + BC->AC + B One example of a single displacement reaction is when magnesium replaces hydrogen in water to make magnesium hydroxide and hydrogen gas: Mg + 2H2O->Mg(OH)2 (v) + H2 (^) Double displacement In a double displacement reaction, the anions and cations of two compounds switch places and form two entirely different compounds.