1. Go to section Pretest 1.Which of the following is an example of a physical change? a.Wood burns and becomes ash. b.A steel nail rusts over time. c.Ice melts and becomes water. d.Milk curdles when acid is added to it. 2.Which of the following characteristics can you determine about a substance based on its chemical formula? a.the number and types of atoms that make up the substance b.the mass of an unknown sample of the substance c.the melting point of the substance d.the density and state of the substance at room temperature Chapter 7

2. Go to section Pretest (continued) 3.How do you find the atomic mass of an element? 4.Which conversion factor would you multiply 0.020 m by in order to express the quantity in centimeters? a.1000 m/1 km b.1 km/1000 m c.1 m/100 cm d.100 cm/1 m 5.Which is the correct chemical formula for potassium hydroxide? a.POH b.KOH c.P 5 OH d.K 2 OH Chapter 7

3. Go to section Interest Grabber Equation Analogy Imagine that you work at a skateboard shop and you are in charge of assembling the skateboards. Every skateboard requires one deck (the board), two trucks (the mounted axles), and four wheels. 1.Your boss asks you to make five skateboards. How many trucks do you need? 2.The following diagram shows the “recipe” for one skateboard. What do you notice about the relative amounts of each part on either side of the arrow? Section 7.1

4. Go to section Burning of Carbon Figure 2

5. Go to section Burning of Carbon Figure 2

6. Go to section Burning of Carbon Figure 2

7. Go to section Balancing Chemical Equations Section 7.1

8. Go to section Balancing Chemical Equations Section 7.1

9. Go to section Balancing Chemical Equations Section 7.1

10. Go to section Balancing Chemical Equations Section 7.1

11. Go to section Calculations With Chemical Equations Figure 8

12. Go to section Calculations With Chemical Equations Figure 8

13. Go to section Calculations With Chemical Equations Figure 8

14. Go to section Calculations With Chemical Equations Figure 8

15. Go to section Calculations With Chemical Equations Figure 8

16. Go to section Interest Grabber Models of Reactions The following drawings represent reactants and products of three different chemical reactions. Section 7.2 Click the mouse button to display the answer. 1.Synthesis means “putting something together.” Which drawing represents a synthesis reaction? Explain your answer. Reaction B is a synthesis reaction, because the two reactants come together to make one product.

17. Go to section Interest Grabber Models of Reactions The following drawings represent reactants and products of three different chemical reactions. Section 7.2 2.Decomposition means “taking something apart.” Which drawing represents a decomposition reaction? Explain your answer. Reaction A is a decomposition reaction, because the reactant is taken apart to make two products. Click the mouse button to display the answer.

18. Go to section Interest Grabber Models of Reactions The following drawings represent reactants and products of three different chemical reactions. Section 7.2 Click the mouse button to display the answer. 3. Replacement means “something taking the place of another.” Which drawing represents a replacement reaction? Explain your answer. Reaction C is a replacement reaction, because one reactant takes the place of part of another.

19. Go to section Reading Strategy Previewing Section 7.2 a. Decomposition b.Double Replacement c.AB → A + B d.A + BC → B + AC e.AB + CD → AD + CB

20. Go to section Reading Strategy a.releases energy to the surroundings b.absorbs energy from surroundings Section 7.3 Comparing and Contrasting

21. Go to section Combustion of Propane Figure 17

22. Go to section Combustion of Propane Figure 17

23. Go to section Combustion of Propane Figure 17

24. Go to section Combustion of Propane Figure 17

25. Go to section Reaction Energy Diagram for an Exothermic Reaction Figure 18A

26. Go to section Reaction Energy Diagram for an Exothermic Reaction Figure 18A

27. Go to section Reaction Energy Diagram for an Endothermic Reaction Figure 18B

28. Go to section Reaction Energy Diagram for an Endothermic Reaction Figure 18B

29. Go to section Reading Strategy Building Vocabulary Section 7.4 a.Temperature d. Concentration b.Surface areae. Catalysts c.Stirring

30. Go to section Reaction Energy Diagram for a Catalyzed and an Uncatalyzed Reaction Figure 23

31. Go to section Physical Equilibrium Figure 25

32. Pretest Answers Chapter 7 Click the mouse button to display the answers. 1.Which of the following is an example of a physical change? a.Wood burns and becomes ash. b.A steel nail rusts over time. c.Ice melts and becomes water. d.Milk curdles when acid is added to it. 2.Which of the following characteristics can you determine about a substance based on its chemical formula? a.the number and types of atoms that make up the substance b.the mass of an unknown sample of the substance c.the melting point of the substance d.the density and state of the substance at room temperature

33. Chapter 7 Pretest Answers (continued) Click the mouse button to display the answers. 3.How do you find the atomic mass of an element? 4.Which conversion factor would you multiply 0.020 m by in order to express the quantity in centimeters? a.1000 m/1 km b.1 km/1000 m c.1 m/100 cm d.100 cm/1 m 5.Which is the correct chemical formula for potassium hydroxide? a.POH b.KOH c.P 5 OH d.K 2 OH The atomic mass of each element is listed on the periodic table.

34. Interest Grabber Answers 1.Your boss asks you to make five skateboards. How many trucks do you need? 10 2.The following diagram shows the “recipe” for one skateboard. What do you notice about the relative amounts of each part on either side of the arrow? There are the same numbers of each part on either side of the arrow. Section 7.1

35. Chapter 7 Go Online Self-grading assessment Articles on chemical reactions For links on conservation of mass, go to www.SciLinks.org and enter the Web Code as follows: ccn-1071.www.SciLinks.org For links on oxidation and reduction, go to www.SciLinks.org and enter the Web Code as follows: ccn-1072.www.SciLinks.org For links on factors affecting reaction rate, go to www.SciLinks.org and enter the Web Code as follows: ccn-1074. www.SciLinks.org For links on factors affecting equilibrium, go to www.SciLinks.org and enter the Web Code as follows: ccn-1075. www.SciLinks.org For links on chemical reactions, go to www.SciLinks.org and enter the Web Code as follows: ccn-1076.www.SciLinks.org

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