Science Notes PDF

Types of Chemical Reactions double ,...

Types of Chemical Reactions double , replacement Chemical reactions can be classified as one of six main types: Synthesis decomposition single replacement, , , neutralization lacid-base) , and combustion. You can identify each type of reaction by examining the reactants This. makes it possible to classify a reaction predict the idenity words to know I of the and then products. combustion Classifying Chemical Reactions decomposition identified of reactions : Chemists have six common types Synthesis decomposition single replacement double replacement , , , double replacement, neutralization lacid-base) , and combustion. These six general types reprsent thousands neutralization lacid-base) of reactions. precipitate single replacement Synthesis Synthesis In a synthesis /combustion) reaction , two or more reactants /Hand B) combine to produce a single product (ABI · element + element - > compound · A + B - > AB ↳ (the Letters A and B reprsent elements ( · Example I : To make table salt in a synthesis reaction , two atoms of sodium metal (Na) and one molecule of chlorine gas (2) react to form Sodium Chloride , NAC diatomic molecule , Uz Chlorine occurs as diatomic molecule when it is a. pure element ↳ Notice that Chlorine is written as a · a There are seven common diatomic elements : Hz , N2 , 02 , Fz/Cle , Brz , and 12. When diatomic elements are not combined into a two atoms. compound they exist , as molecules containing · Example 2: Magnesium metal/Mg) reacts with oxygen gas (02) to form magnesium oxide , MgO. The balanced chimical equation is : · 2MgtO- > ZMgO to form ionic compound. When Synthesis reactions between metal previous examples two elements combined an occur a ↳ In both , non-metal , electrons are transferred from the metal to the non-metal producing ions. For ionic compounds you can use the ior and a , , equation. For multivalent metal , such iron charges to predict the product and write the covalent compounds or when a as copper or , is involved , it is more difficult to predict the product. In these cases , you will need extra information to complete the chemical equation to form dinitrogen monoxide (N2O) called nitrous oxide The balanced Example 3: Nitrogen gas (N2) react with oxygen gas (02) also. · can , for this reaction is : equation · 2Ne + 02- > INz0  Decomposition Reactions is breaking compound into smaller compounds separate. A decomposition reaction the reverse of a A decomposition reaction down of a or elements is reaction Synthesis element + element · Compound - > · AB- > A+B o Example 1: Table salt can be decomposed into sodium metal and chlorine gas by melting it at 800°C and passing an electric current through the liquid salt. This is one way to produce sodium metal. > [Nacl- > IWa + Cl2 passed through. it About 4 percent of hydrogen gas used in the world is produced · Example 2 : Water decomposes when an electric current is the called electrolysis. by decomposition. Decomposing water by passing an electric current through water is ↳ THO --2H2 to2 In both decomposition examples above , compound consisting of two elements is decomposed original into decomposition a · the elements. During of an ionic compound , electrons transfer back to the atoms of the metal and each element becomes electrically neutral. As a result , neither of the products is an ion. Single Replacement Reactions single replacement reaction , reactive element /a metal non-metal) and compound react to produce element and another In a a or a a another words , of the elements is replaced by another element The element that is replaced could be metal non-metal. compound. In other one. a or a · element + compound - > element + compound BC > BHAC where A is metal At - · · A+ BC - > C+ BA where A is a non-metal · Example 1 : An example of a single replacement reaction involving copper occurs when copper is placed into a solution of silver nitrate. ↳ Cu + ZAgNOs - > zAg + Cu(NO3Iz non-metal element is combined with a compound the non-metal · Example 2: When a , will replace the other non-metal For. example , fluorine replaces iodive in sodium iodide ↳ F + INal - > Iz + 7 NaF