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| Understanding the concepts
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Check your answers |
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| 1.
| What is a precipitation reaction? Some ionic compounds dissolve in water. What happens when soluble ionic compounds dissolve? Some ionic compounds are insoluble in water. What does this mean? Solubility rules are commonly used to predict if an ionic compound is soluble in water. Open the General Rules for Solubility of Ionic Compounds (Salts) at 25°C Table on the Web site to review these rules.
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| 2.a.
| Open the Precipitation Reactions Understanding Concepts on the CD and go through the Introduction and Example. (Make sure you click through all the screens of the Introduction to see the video clip and the animation.) The animation of silver chloride is important to understand. What is the blue ball in the animation? What ion is missing from the animation? Consider the reaction between 4 formula units of Pb(NO3)2(aq) and 3 formula units of CaCl2(aq). After precipitate formation is complete, how many and which type of ions remain in solution? Understanding atomic level views of precipitation reactions is extremely important. Drawing a picture may help. |
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| b.
| Next, do the Exercises in the Understanding Concepts to practice predicting whether a precipitate will form. Reference the Solubility Rules if you need help predicting insoluble ionic compounds. |
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| c.
| Precipitation reactions are described in one of three equations: molecular, complete ionic, and net ionic. What is the difference between these three types of reactions? For each Exercise you do in the Exploration above, predict the net ionic equation that occurs when a precipitate forms. Click Answer to see if your equation is correct. |
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| 3.
| To practice writing molecular and net ionic equations, do Problems 7.18, 7.20, 7.22, and 7.26 in the text.
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| 4.
| Soluble ionic compounds are strong electrolytes. What does this mean? Strong acids and strong bases are also strong electrolytes. Explain. When a strong acid reacts with a strong base, what product is produced? What is the net ionic equation? For practice balancing acid-base reactions, do Problems 7.39 and 7.40 in the text. |
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| 5.
| What is an oxidation-reduction reaction? Open the Zinc and Iodine Visualization on the CD to view an example of an oxidation-reduction reaction. How are electrons gained and lost in this reaction? For more practice with oxidation-reduction reactions, do Problems 7.48 and 7.50 in the text. |
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| 6.
| What are combustion reactions? Synthesis (combination) reactions? Decomposition reactions? Play the Ammonium Dichromate Volcano Visualization on the CD to see an example of a decomposition reaction. |
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| 7.
| Open Key Words on the CD and test your ability to define the important terms presented in Chapter 7. |
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| 8.
| Test your understanding of Chapter 7 by taking the ACE quizzes on the Web site. |
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