Chapter 7 Chemical Formulas And Compounds Test B Answers

Chapter 7 Chemical Formulas And Compounds Test B Answers Chapter 7 Chemical Formulas and Compounds Test B Answers This document provides the answers and explanations for the Chapter 7 test focusing on chemical formulas and compounds specifically designed for Test B 1 Multiple Choice This section comprises 20 multiplechoice questions testing fundamental concepts like chemical formulas naming compounds and basic understanding of ionic and covalent bonds Each question provides four answer choices with only one being the correct answer Answers will include the letter representing the correct choice and a brief explanation justifying the selection 2 TrueFalse This section contains 10 truefalse questions covering more advanced topics like oxidation states polyatomic ions and common chemical formulas Answers will indicate whether the statement is true or false accompanied by an explanation elaborating on why 3 Short Answer This section features 5 short answer questions requiring students to demonstrate their understanding through explanations and examples The questions cover topics like writing chemical formulas predicting the type of bond between elements and analyzing chemical reactions Each answer will provide a detailed explanation with relevant examples to illustrate the concepts 4 Matching This section presents 10 terms related to chemical formulas and compounds that students need to match with their corresponding definitions Answers will include the matching term for each definition Note This document is intended to be used as a study guide and is not a substitute for thorough understanding of the material It is crucial for students to consult their textbook and notes for a comprehensive understanding of the concepts 2 Disclaimer The following answers are based on general chemistry principles and may vary depending on the specific curriculum and textbook used Multiple Choice 1 Which of the following is the correct formula for potassium chloride a KCl b KCl2 c K2Cl d K2Cl2 Answer a KCl Explanation Potassium K is in group 1 and has a 1 charge while chlorine Cl is in group 17 and has a 1 charge To balance the charges one potassium ion combines with one chloride ion 2 Which of the following is an ionic compound a CO2 b H2O c NaCl d CH4 Answer c NaCl Explanation NaCl is formed by a metal Na and a nonmetal Cl indicating an ionic bond 3 What is the name of the compound with the formula Fe2O3 a Iron oxide b Iron II oxide c Iron III oxide d Iron trioxide Answer c Iron III oxide Explanation Iron Fe has a 3 charge in this compound while oxygen O has a 2 charge The Roman numeral III indicates the oxidation state of iron 4 What is the chemical formula for sulfur dioxide a SO b SO2 c S2O d S2O2 3 Answer b SO2 Explanation Sulfur S has a 4 charge and oxygen O has a 2 charge in this compound The formula balances the charges with one sulfur atom and two oxygen atoms 5 Which of the following elements forms only covalent bonds a Sodium Na b Chlorine Cl c Carbon C d Calcium Ca Answer c Carbon C Explanation Carbon is a nonmetal and typically forms covalent bonds with other nonmetals 6 What is the name of the compound with the formula Na2SO4 a Sodium sulfide b Sodium sulfate c Sodium sulfur oxide d Disodium sulfate Answer b Sodium sulfate Explanation This compound contains the polyatomic ion sulfate SO4 with a 2 charge The two sodium ions Na each have a 1 charge balancing the overall charge 7 Which of the following is the correct formula for magnesium chloride a MgCl b MgCl2 c Mg2Cl d Mg2Cl2 Answer b MgCl2 Explanation Magnesium Mg has a 2 charge and chlorine Cl has a 1 charge To balance the charges one magnesium ion combines with two chloride ions 8 What is the chemical formula for calcium phosphate a CaPO4 b Ca3PO42 c Ca2PO43 d CaPO43 Answer b Ca3PO42 Explanation Calcium Ca has a 2 charge while the phosphate ion PO4 has a 3 charge 4 To balance the charges three calcium ions combine with two phosphate ions 9 Which of the following is a covalent compound a KBr b MgO c CO2 d LiF Answer c CO2 Explanation CO2 is formed by two nonmetals carbon C and oxygen O indicating a covalent bond 10 What is the name of the compound with the formula NH3 a Nitrogen hydride b Ammonia c Nitrogen trihydride d Ammonium Answer b Ammonia Explanation NH3 is a wellknown compound with the common name ammonia 11 Which of the following elements has a variable oxidation state a Sodium Na b Iron Fe c Oxygen O d Chlorine Cl Answer b Iron Fe Explanation Iron can exist in different oxidation states such as 2 and 3 depending on the compound it forms 12 What is the chemical formula for sulfuric acid a H2SO3 b H2SO4 c HSO4 d H2S Answer b H2SO4 Explanation Sulfuric acid contains two hydrogen ions H one sulfur atom S and four oxygen atoms O 5 13 Which of the following is the correct formula for aluminum oxide a AlO b Al2O3 c Al3O2 d AlO2 Answer b Al2O3 Explanation Aluminum Al has a 3 charge and oxygen O has a 2 charge To balance the charges two aluminum ions combine with three oxygen ions 14 What is the name of the compound with the formula CuSO4 a Copper sulfate b Copper I sulfate c Copper II sulfate d Copper sulfur oxide Answer c Copper II sulfate Explanation Copper Cu has a 2 charge in this compound while the sulfate ion SO4 has a 2 charge The Roman numeral II indicates the oxidation state of copper 15 Which of the following is a binary compound a Na2CO3 b H2O c CaOH2 d KMnO4 Answer b H2O Explanation A binary compound is composed of two elements H2O contains only hydrogen H and oxygen O 16 What is the chemical formula for lithium nitride a LiN b Li3N c Li2N3 d LiN3 Answer b Li3N Explanation Lithium Li has a 1 charge and nitrogen N has a 3 charge To balance the charges three lithium ions combine with one nitrogen ion 17 Which of the following is a polyatomic ion 6 a Cl b SO4 2 c Na d Mg2 Answer b SO4 2 Explanation A polyatomic ion is a group of two or more atoms bonded together that carries a net charge SO4 2 represents the sulfate ion 18 What is the name of the compound with the formula HNO3 a Hydrogen nitrate b Nitric acid c Nitrogen trioxide d Hydrogen nitrite Answer b Nitric acid Explanation HNO3 is a wellknown compound with the common name nitric acid 19 Which of the following elements forms only ionic bonds a Oxygen O b Carbon C c Potassium K d Nitrogen N Answer c Potassium K Explanation Potassium is a metal and typically forms ionic bonds with nonmetals 20 What is the chemical formula for carbon tetrachloride a CCl b CCl2 c CCl3 d CCl4 Answer d CCl4 Explanation Carbon C has a 4 charge and chlorine Cl has a 1 charge To balance the charges one carbon atom combines with four chlorine atoms TrueFalse 1 The chemical formula for sodium oxide is NaO Answer False 7 Explanation Sodium oxide has the chemical formula Na2O as sodium has a 1 charge and oxygen has a 2 charge 2 Covalent compounds are typically formed between a metal and a nonmetal Answer False Explanation Covalent compounds are formed between two or more nonmetals 3 The oxidation state of an element in a compound is always the same Answer False Explanation Some elements can exhibit different oxidation states depending on the compound they form 4 The compound with the formula MgCl2 is named magnesium dichloride Answer False Explanation The correct name is magnesium chloride The prefix di is not used in naming ionic compounds 5 Polyatomic ions can contain both metals and nonmetals Answer True Explanation Polyatomic ions often consist of a combination of nonmetals but some can include a metal such as the permanganate ion MnO4 which includes manganese 6 The chemical formula for water is H2O2 Answer False Explanation The chemical formula for water is H2O containing two hydrogen atoms and one oxygen atom 7 Ionic compounds typically have high melting points Answer True Explanation The strong electrostatic forces between ions in an ionic lattice require significant energy to break resulting in high melting points 8 The chemical formula for ammonia is NH4 Answer False Explanation The chemical formula for ammonia is NH3 NH4 represents the ammonium ion 9 The compound with the formula FeCl3 is named iron III chloride Answer True Explanation Iron Fe has a 3 charge in FeCl3 which is indicated by the Roman numeral III in the compounds name 8 10 Covalent compounds are good conductors of electricity in their solid state Answer False Explanation Covalent compounds do not have freemoving charged particles like ions and are typically poor conductors of electricity in their solid state Short Answer 1 Write the chemical formula for calcium carbonate Answer CaCO3 Explanation Calcium Ca has a 2 charge while the carbonate ion CO3 has a 2 charge The formula balances the charges with one calcium ion and one carbonate ion 2 Predict the type of bond that would form between nitrogen and oxygen Answer Covalent bond Explanation Both nitrogen N and oxygen O are nonmetals and they typically form covalent bonds by sharing electrons 3 What is the oxidation state of sulfur in the compound H2SO4 Answer 6 Explanation Hydrogen has a 1 charge and oxygen has a 2 charge The overall charge of the compound is 0 so the oxidation state of sulfur can be calculated as follows 21 x 42 0 where x is the oxidation state of sulfur Solving for x we get x 6 4 Explain the difference between ionic and covalent compounds Answer Ionic compounds are formed by the electrostatic attraction between oppositely charged ions typically involving a metal and a nonmetal They are usually solid at room temperature have high melting points and are good conductors of electricity when dissolved in water Examples NaCl KBr MgO Covalent compounds are formed by the sharing of electrons between two or more non metals They can be solids liquids or gases at room temperature have relatively low melting points and are generally poor conductors of electricity Examples CO2 H2O CH4 5 Write the balanced chemical equation for the reaction between sodium and chlorine to form sodium chloride Answer 2Na Cl2 2NaCl Explanation The equation shows that two sodium atoms Na react with one chlorine molecule Cl2 to produce two sodium chloride units NaCl The equation is balanced because there are equal numbers of each type of atom on both sides of the equation 9 Matching Match the following terms with their corresponding definitions 1 Chemical formula A symbolic representation of a molecule or compound showing the types and number of atoms present 2 Ionic bond A type of bond formed by the electrostatic attraction between oppositely charged ions 3 Covalent bond A type of bond formed by the sharing of electrons between two or more atoms 4 Oxidation state The charge an atom would have if all the electrons in a compound were distributed according to the rules of electronegativity 5 Polyatomic ion A group of two or more atoms bonded together that carries a net charge 6 Binary compound A compound composed of two elements 7 Empirical formula The simplest wholenumber ratio of atoms in a compound 8 Molecular formula The actual number of atoms of each element in a molecule 9 Anion A negatively charged ion 10 Cation A positively charged ion Answers 1 Chemical formula 2 Ionic bond 3 Covalent bond 4 Oxidation state 5 Polyatomic ion 6 Binary compound 7 Empirical formula 8 Molecular formula 9 Anion 10 Cation