Chapter 9 Chemical Names Formulas Answers Key

Chapter 9 Chemical Names Formulas Answers Key Chapter 9 Chemical Names and Formulas Answers Key Chemistry is the study of matter and its properties and understanding the language of chemistry is crucial for comprehending its complexities This chapter delves into the fundamental principles of naming chemical compounds and writing their corresponding formulas Mastering these skills allows us to communicate effectively about chemical substances and their reactions 91 Naming Ionic Compounds Key Concepts Ionic compounds are formed by electrostatic attractions between oppositely charged ions cations and anions Cations are positively charged ions typically formed by metals Anions are negatively charged ions typically formed by nonmetals Monatomic ions consist of a single atom with a charge Polyatomic ions are groups of atoms that act as a single unit with a net charge Steps for Naming Ionic Compounds 1 Identify the cation and anion 2 Name the cation using its elemental name 3 Name the anion using the root name of the nonmetal followed by ide 4 If the cation has multiple possible charges indicate the charge using Roman numerals in parentheses after the cations name Examples NaCl Sodium chloride FeCl2 IronII chloride FeCl3 IronIII chloride CaCO3 Calcium carbonate 92 Naming Covalent Compounds Key Concepts 2 Covalent compounds are formed by the sharing of electrons between nonmetals Prefixes are used to indicate the number of atoms of each element in a covalent compound The less electronegative element is written first Steps for Naming Covalent Compounds 1 Identify the elements present 2 Use prefixes to indicate the number of atoms of each element 3 Add ide to the second elements name Examples CO2 Carbon dioxide N2O Dinitrogen monoxide PCl5 Phosphorus pentachloride 93 Writing Chemical Formulas Key Concepts Chemical formulas represent the composition of a compound using symbols and subscripts Subscripts indicate the number of atoms of each element in a compound The formula of an ionic compound is determined by balancing the charges of the cation and anion The formula of a covalent compound is determined by the number of atoms of each element indicated by the prefixes in its name Steps for Writing Chemical Formulas 1 Determine the charges of the cation and anion 2 Find the lowest common multiple of the charges 3 Use the subscripts to indicate the number of each ion needed to balance the charges Examples Sodium chloride NaCl Na1 and Cl1 so the formula is NaCl Calcium oxide CaO Ca2 and O2 so the formula is CaO IronIII oxide Fe2O3 Fe3 and O2 so the formula is Fe2O3 94 Naming Acids Key Concepts Acids are compounds that release hydrogen ions H when dissolved in water 3 Binary acids contain hydrogen and one other nonmetal Oxyacids contain hydrogen a nonmetal and oxygen Steps for Naming Acids 1 For binary acids use the prefix hydro followed by the nonmetal name with the ic suffix 2 For oxyacids use the root name of the nonmetal with ic or ous suffix based on the number of oxygen atoms 3 Add acid to the end of the name Examples HCl Hydrochloric acid H2SO4 Sulfuric acid HNO3 Nitric acid 95 Writing Chemical Equations Key Concepts Chemical equations represent chemical reactions using symbols and formulas Reactants are the substances that react Products are the substances that are formed Coefficients are numbers placed in front of chemical formulas to balance the number of atoms of each element on both sides of the equation Steps for Balancing Chemical Equations 1 Write the unbalanced equation 2 Adjust the coefficients in front of each formula until the number of atoms of each element is the same on both sides of the equation 3 Check the balance of the equation Examples 2H2 O2 2H2O combustion of hydrogen CH4 2O2 CO2 2H2O combustion of methane Answers Key This section provides the answers to practice problems and exercises presented in the chapter It can be used to selfcheck understanding and identify areas for improvement 4 Practice Problem Solutions Problem 1 Name the following compounds a KBr b MgCl2 c Al2O3 Answer a Potassium bromide b Magnesium chloride c Aluminum oxide Problem 2 Write the chemical formula for the following compounds a IronIII sulfide b Carbon monoxide c Sulfur trioxide Answer a Fe2S3 b CO c SO3 Exercise Solutions Exercise 1 Name the following compounds a Na2S b CaO c Li3N d MgF2 Answer a Sodium sulfide b Calcium oxide c Lithium nitride d Magnesium fluoride Exercise 2 Write the chemical formula for the following compounds a CopperI chloride b TinIV oxide c Silver sulfide d LeadII bromide Answer a CuCl b SnO2 c Ag2S d PbBr2 Conclusion This chapter lays a solid foundation for understanding and working with chemical compounds By mastering the naming and formula writing skills presented students are empowered to communicate effectively about the vast world of chemistry Remember to practice and review the concepts regularly to solidify your knowledge and build confidence in navigating the chemical landscape