Naming Chemical Compounds PDF

Summary

This document provides a detailed explanation about the naming system for different types of chemical compounds. It covers various categories including ionic, molecular, and oxoacids. The document explains naming conventions from basic chemistry to more complex cases.

Full Transcript

Naming Compounds Compounds are: 1-Organic compounds 2- Inorganic compound 1-Organic compounds contain carbon, usually in combination with elements such as H, O, N, and S Some carbon-containing compounds, such as carbon monoxide (CO), carbon dioxide (CO2), carbon di...

Naming Compounds Compounds are: 1-Organic compounds 2- Inorganic compound 1-Organic compounds contain carbon, usually in combination with elements such as H, O, N, and S Some carbon-containing compounds, such as carbon monoxide (CO), carbon dioxide (CO2), carbon disulfide (CS2), compounds containing the cyanide group (CN2), and carbonate (CO3) -2) and bicarbonate (HCO3) -) groups are considered to be inorganic compounds... 2- Inorganic compounds: four categories: 1-ionic compounds, 2- molecular compounds, 3- acids and bases, 4- and hydrates. 1- Ionic Compounds ionic compounds are made up of cations (positive ions) and anions (negative ions). ( With important exception of ammonium ion, NH4+ ) All cations are derived from metal atoms. Metal cations take their names from the elements. Example : Sodium chloride NaCl Potassium bromide (KBr), zinc iodide (ZnI2), aluminum oxide (Al2O3) Non metallic anion is named by taking first part of element name (chlorine) and adding “-ide.” 1- Ionic Compounds Certain metals, especially the transition metals, can form more than one type of cation. example. Iron can form two cations: Fe 2+ and Fe 3- ending “-ous” is used for cation with fewer positive charges Traditional nomenclature for metals that form only ending “-ic” is used with cation more positive charges two ions. Systematic Traditional nomenclature for nomenclature for ferrous chloride FeCl2 or iron(II) chloride; metals that form metals that form only ferric chloride FeCl 3 or iron(III) chloride. more than one type two ions. of cation 1- Ionic Compounds Systemic nomenclature for metallic elements that have two or more different positive charges in compound: Example magnanese Mn 2+ Mn 3+ Mn 4+ Roman numeral I indicates one positive charge, II means two positive charges, and so on Example Mn 2+: MnO manganese(II) oxide (“manganese-two oxide,”) Mn 3+: Mn2O3 manganese(III) oxide (manganese-three oxide) Mn 4+: MnO2 manganese(IV) oxide (manganese-four oxide) 2- Molecular Compounds: contain discrete molecular units.. name of first element in formula first, and second element is named by adding -ide Some examples are For one pair ofelements to form several different compounds: use of Greek prefixes to denote number of atoms of each element present CO carbon monoxide SO2 sulfur dioxide NO2 nitrogen dioxide CO2 carbon dioxide SO3 sulfur trioxide N2O4 dinitrogen tetroxide Guidelines for naming compounds with prefixes: Prefix “mono-” may be omitted for first element. Example, PCl3 is named phosphorus trichloride, not monophosphorus trichloride.. For oxides, ending “a” in prefix is sometimes omitted. Example, N2O4 may be called dinitrogen tetroxide rather than dinitrogen tetraoxide. 2- Molecular Compounds: Acids and Bases Naming Acids An acid can be described as a substance that yields hydrogen ions (H+) when dissolved in water. a- For simple acids : contain one or more hydrogen atoms as well as an anionic group. For naming these acids: Anions whose names end in “-ide” form acids with a “hydro-” prefix and an “-ic” ending, In some cases two different names are used for same chemical formula: HCl hydrogen chloride HCl hydrochloric acid When it is dissolved in water, Naming Acids b- Oxoacids : are acids that contain hydrogen, oxygen, and another element (central element). For naming these oxoacids: Use the following common acids as references in naming oxoacids: H2CO3 carbonic acid HClO3 chloric acid HBrO3 bromic acid HNO3 nitric acid H3PO4 phosphoric acid H2SO4 sulfuric acid Naming Acids C- oxo acids that have same central atom but a different number of O atoms. For naming these compounds we use the following rules : 1. Addition of one O atom to the “-ic” acid: The acid is called “per... -ic” acid. Example: adding an O atom to HClO3 ( chloric acid) changes chloric acid to perchloric acid, HClO4. 2. Removal of one O atom from the “-ic” acid: The acid is called “-ous” acid. Example nitric acid, HNO3, becomes nitrous acid, HNO2. 3. Removal of two O atoms from the “-ic” acid: The acid is called “hypo... –ous”acid Example: when HBrO3 is converted to HBrO, acid is called hypobromous acid Adding Oxygen, converts (-ic) acid to per…ic acid e.g:HClO3→HClO4 Chloric acid →perchloric acid Removing oxygen atom, converts (-ic) acid to (-ous) acid Oxoacids e.g. HNO3 → HNO2 Nitric acid → nitrous acid Removing two oxygen atoms, converts (-ic) acid to (hypo…..ous) acid e.g. HBrO3 → HBrO Bromic acid → Hypobromous acid Naming Bases A base can be described as a substance that yields hydroxide ions (OH-) when dissolved in water. NaOH sodium hydroxide KOH potassium hydroxide Ba(OH)2 barium hydroxide Not all base contains hydroxide in its structure , example Ammonia (NH3), it is a molecular compound in gaseous or pure liquid state, is also classified as a common base. ammonia dissolves in water, NH3 reacts partially with water to yield NH4 - and OH- ions 4- Hydrates: Hydrates are compounds that have a specific number of water molecules attached to them Example, CuSO4. 5H2O :each unit of copper(II) sulfate has five water molecules associated with it. For naming this compound is copper(II) sulfate pentahydrate, and its formula is written as CuSO4.5H2O. Water molecules can be removed by heating. resulting in CuSO4, called anhydrous copper(II) sulfate

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