Choose the answer that best completes each statement.

Transcription

1 Name Date CHAPTER TEST: CHEMICAL BONDS AND EQUATIONS Multiple Choice Choose the answer that best completes each statement. 1. Magnesium bromide is an ionic compound with the chemical formula MgBr2. What does the 2 tell you? a. Bromide has a 2 charge. b. There are two magnesium ions to every bromide ion. c. There are two bromide ions for every magnesium ion. d. Bromide has a 2+ charge. 2. When an atom loses an electron, it becomes a. a. positive ion b. negative ion c. neutral ion d. neutral atom 3. An ionic bond is the attraction between. a. similarly charged ions b. oppositely charged ions c. neutral ions d. neutral atoms 4. Ions that are made of more than one atom are examples of. a. polyatomic ions b. negative ions c. positive ions d. neutral ions 5. What is the chemical name for the compound with the formula Na2S? a. sodium fluoride b. magnesium sulfide c. lithium oxide d. sodium sulfide 6. A chemical bond formed when two atoms share electrons is called a (an). a. ionic bond b. covalent bond c. polyatomic bond d. crystal bond 7. What is a double bond? a. a bond between two atoms b. one pair of electrons shared between two atoms c. two pairs of electrons shared between two atoms d. two pairs of electrons shared between four atoms Chemical Bonds and Equations Nitty Gritty Science, LLC

2 8. A covalent bond in which electrons are shared unequally is. a. polar b. a double bond c. ionic d. polyatomic 9. Electrons involved in bonding between atoms are. a. valence electrons b. inside the nucleus c. closest to the nucleus d. positively charged 10. What is the greatest number of valence electrons an atom can have? a. 2 b. 3 c. 8 d What happens when chemical bonds break and new bonds form? a. a physical change b. a chemical reaction c. matter is destroyed d. surface area increases 12. CaCO3 represents a chemical. a. symbol b. formula c. subscript d. reaction 13. The only sure evidence for a chemical reaction is. a. the formation of a gas b. a color change c. the production of one or more new substances d. changes in properties 14. A shorter, easier way to show chemical reactions, using symbols instead of words, is called a. a. chemical equation b. chemical formula c. symbol d. subscript 15. The substances listed on the left side of a chemical equation are the. a. products b. coefficients c. precipitates d. Reactants Chemical Bonds and Equations Nitty Gritty Science, LLC

3 16. Which of the following is a balanced chemical equation? a. H2O2 H2O + O2 b. 2 Fe2O3 + 3 C 4 Fe + 3 CO2 c. SO2 + O2 + 2 H2O 4 H2SO4 d. 2 Mg + HC1 MgCl2 + H2 17. A chemical reaction that absorbs energy in the form of heat is described as a. endothermic b. exothermic c. combustion d. unbalanced Fill-in-the-blank Complete each statement with the correct vocabulary term. 18. When an atom gains an electron it becomes a ion. 19. The attraction between a positive ion and a negative ion results in bond. 20. When electrons are between two atoms, a covalent bond is formed. 21. Nitrate (NO3 ), ammonium (NH4 + ), and carbonate (CO3 2 ) are examples of ions. 22. Bonds that form between two nonmetal atoms usually are bonds. 23. Elements in Group 1 lose one electron to form ions with a (an) charge. 24. In a chemical equation, a (an) tells you how many atoms or molecules of a reactant or a product take part in a reaction. 25. The principle of states that during a chemical reaction, matter is not created or destroyed. Chemical Bonds and Equations Nitty Gritty Science, LLC

4 Use the diagram to answer each question. Interpreting Diagrams Equation A Equation B Cu(s)+ 2AgNO 3(aq) Cu(NO 3) 2(aq)+2Ag(s) 2Al2O 3(I) 4Al (I)+ 3O 2(g) 26. What are the reactants in: Equation A: Equation B: 27. What are the products in: Equation A: Equation B: 28. What do the coefficients tell you about the ratio of the reactants in: Equation A: Equation B: 29. What is the physical state of the products in: Equation A: Equation B: 30. Write Equation A as a sentence: Chemical Bonds and Equations Nitty Gritty Science, LLC

5 Use the diagram to answer each question. 31. Which letter represents decomposition? 32. Which letter represents single displacement? 33. Which letter represents synthesis? 34. Which letter represents double displacement? Chemical Bonds and Equations Nitty Gritty Science, LLC

6 Essay Choose TWO essays and answer using the space provided. 35. Compare a covalent bond and an ionic bond. 36. For each situation described below, tell whether the reaction is endothermic or exothermic. Explain your reasoning in terms of the energy of the reactants and products. A) A log burns in a fireplace, giving off gases and leaving behind ash. B) When vinegar and baking soda are mixed, new substances form and the solution becomes cooler. 37. Describe the difference between a synthesis reaction and a decomposition reaction. Chemical Bonds and Equations Nitty Gritty Science, LLC

7 Essay 1 Essay 2 Chemical Bonds and Equations Nitty Gritty Science, LLC

8 ANSWER KEY CHAPTER TEST: Chemical Bonds and Equations MULTIPLE CHOICE 1. C 2. A 3. B 4. A 5. D 6. B 7. C 8. A 9. A 10. C 11. B 12. B 13. C 14. A 15. D 16. B 17. A FILL-IN-THE-BLANK 18. negative 19. an ionic 20. shared 21. polyatomic 22. covalent positive 24. coefficient 25. conservation of mass INTERPRETING DIAGRAMS 26. copper, silver nitrate: aluminum oxide 27. copper nitrate, silver; aluminum, oxygen molecule copper: 2 molecules silver nitrate; 2 molecules silver oxide 29. solid, aqueous; liquid 30. Solid copper plus two molecules of silver nitrate dissolved in water yields dissolved copper nitrate plus two molecules of solid aluminum 31. C 32. A 33. B 34. D Chemical Bonds and Equations Nitty Gritty Science, LLC

9 ESSAY 35. A covalent bond is formed when two atoms share valence electrons. Neither atom loses electrons or takes electrons from the other. No charged particles form. In an ionic bond, one or more electrons are transferred from one atom to another. Atoms that lose electrons become positively charged ions, and atoms that gain electrons become negatively charged ions. These oppositely charged particles then attract each other. 36. A) The reaction is exothermic because heat and light are given off. The energy of the products is less than the energy of the reactants. B) The reaction is endothermic. Energy is absorbed by the reaction, making the solution feel cooler. The energy of the products is greater than the energy of the reactants. 37. A synthesis reaction produces a more complex substance from simpler substances. A decomposition reaction produces simpler substances from a more complex substance. These two reactions are opposite processes. Chemical Bonds and Equations Nitty Gritty Science, LLC