CHAPTER 7 CHEMICAL REACTIONS: AN INTRODUCTION

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1 Chemistry Name Hour Chemistry Approximate Timeline Students are expected to keep up with class work when absent. CHAPTER 7 CHEMICAL REACTIONS: AN INTRODUCTION Day Plans for the day Assignment(s) for the day 1 Begin Chapter Evidence of Chemical Reactions o Demonstrate several chemical reactions Assignment 7.0 Assignment 7.1 Read section(s) Chemical Equations o Writing chemical equations 2 Quiz 7.1 Evidence of Chemical Reactions Assignment 7.2 Assignment 7.3a 7.3 Balancing Chemical Equations o Writing chemical equations o Balancing chemical equations Balancing Chemical Equations Assignment 7.3b 4 Quiz 7.2 Writing & Balancing Assignment 7.4 Chemical Equations Work on Assignment Grade & discuss Assignment 7.4 Review for chapter 7 test 6 Chapter 7 Test Read section(s) 8.3

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3 Chemistry Name Hour Study Guides Chapter 7 Quizzes Quiz Evidence of Chemical Reactions 1. List several signals that a chemical reaction has occurred. 7.2 Chemical Equations 2. Define the following terms. a. Chemical reaction b. Chemical equation c. Reactant d. Product 3. When looking at a chemical equation, what is found : a. to the left of the arrow? b. to the right of the arrow? 4. What do the following symbols mean when found in a chemical equation? e. (s) f. (l) g. (g) h. (aq) Quiz 7.3 Balancing Chemical Equations 1. What is indicated by the coefficients in a balanced chemical equation? 2. We cannot change the of any reactant or product when we balance a chemical equation. We can only place in front of the formulas. 3. Be able to balance several chemical equations.

4 Study Guide Chapter 7 Test At the completion of chapter 7 you should 1. Know the definitions of the following terms a. Chemical reaction b. Chemical equation c. Reactants d. Products e. Balancing the chemical equation f. Coefficients 2. Know several clues that indicate a chemical reaction has occurred 3. Know the parts of a chemical equation a. reactant side b. product side c. what the arrow means d. the meaning of i. (s) ii. (l) iii. (g) iv. (aq) 4. Be able to balance chemical equations 5. Know how coefficients are used in chemical equations

5 Chemistry Name Hour Assignment 7.0 Vocabulary 1. Chemical reaction 2. Chemical equation 3. Reactants 4. Products 5. Balancing the chemical equation 6. Coefficients

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7 Chemistry Name Hour Assignment 7.1 Evidence of a Chemical Reaction (2 pages) 1) What types of evidence indicate that a chemical reaction has taken place? 2) Give an example of each type of clue from Table 7.1 (page 219) that a chemical reaction has taken place. A) B) C) D) 3) Look at the photographs at the bottom of page 219. Identify any clues that tell you a chemical reaction has taken place. A) B) C) D) 4) Identify the reactants and products and write chemical equations for each of the following reactions. Do not balance the equation. A) Gaseous chlorine reacts with an aqueous solution of potassium bromide to form liquid bromine and an aqueous solution of potassium chloride. B) Solid aluminum reacts with solid iodine to produce solid aluminum iodide. C) Solid magnesium reacts with an aqueous solution of hydrochloric acid to form an aqueous solution of magnesium chloride and bubbles of hydrogen gas.

8 5) List several pieces of information you can determine about a chemical reaction just by reading the chemical equation. 6) A) What is the difference between a coefficient and a subscript in a chemical equation? B) Provide an example of each. 7) A) What is the difference between an aqueous solution and a liquid? B) Write the symbols for each.

9 Chemistry Name Assignment 7.2 Writing Chemical Equations Write, but do not balance, the chemical equation for each reaction described below. 1) Nitrogen gas reacts with hydrogen gas to produce ammonia gas. Hour 2) Calcium metal reacts with aqueous aluminum (III) chloride to produce aqueous calcium chloride and aluminum metal. 3) When sodium metal reacts with water, aqueous sodium hydroxide and hydrogen gas are formed. 4) Acetylene gas (C 2 H 2 ) reacts with oxygen gas to form carbon dioxide gas and water vapor. 5) Solid lead reacts with sodium metal and solid vinyl chloride (C 2 H 5 Cl) to produce tetraethyl lead, Pb(C 2 H 5 ) 4, and table salt. 6) Aqueous phosphoric acid is produced from the reaction of solid tetraphosphorus decaoxide and water. 7) The reaction of aqueous barium chloride with aqueous aluminum (III) sulfate forms solid barium sulfate and aqueous aluminum (III) chloride. 8) Butane gas (C 4 H 10 ) burns with oxygen gas and chlorine gas to yield carbon dioxide gas, liquid carbon tetrachloride, and water vapor. 9) Aqueous phosphoric acid and aqueous dichlorine heptaoxide are produced when aqueous perchloric acid and solid tetraphosphorus decaoxide react.

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11 Chemistry Name Hour Assignment 7.3a Balancing Chemical Equations Balance each of the following. 1) Ca(OH) 2 + HCl ---> CaCl 2 + H 2 O 2) PbO 2 ---> PbO + O 2 3) Al(NO 3 ) 3 + H 2 SO 4 ---> Al 2 (SO 4 ) 3 + HNO 3 4) C 4 H 10 + O 2 ---> CO 2 + H 2 O 5) CaO + H 2 O ---> Ca(OH) 2 6) P 2 O 5 + BaO ---> Ba 3 (PO 4 ) 2 7) Cu + AgNO 3 ---> Cu(NO 3 ) 2 + Ag 8) NaOH ---> Na 2 O + H 2 O 9) C 6 H 12 + O 2 ---> CO 2 + H 2 O 10) Al + Pb(NO 3 ) 2 ---> Al(NO 3 ) 3 + Pb 11) Ca(AlO 2 ) 2 + HCl ---> AlCl 3 + CaCl 2 + H 2 O 12) NH 4 NO 2 ---> H 2 O + N 2 13) H 2 SO 4 ---> H 2 O + SO 3 14) BaCO 3 + C + H 2 O ---> CO + Ba(OH) 2 15) Br 2 + H 2 O + SO 2 ---> HBr + H 2 SO 4 16) NaCl + H 2 SO 4 ---> HCl + Na 2 SO 4 17) AgNO 3 + K 2 SO 4 ---> Ag 2 SO 4 + KNO 3 18) NH 3 + O 2 ---> N 2 O 4 + H 2 O 19) CeO 2 + KI + HCl ---> KCl + CeCl 3 + H 2 O + I 2 20) Pb(C 2 H 3 O 2 ) 2 + K 2 CrO 4 ---> PbCrO 4 + KC 2 H 3 O 2

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13 Chemistry Name Assignment 7.3b Writing & Balancing Chemical Equations Hour 1) Write and balance each of the following chemical equations. A) Gaseous chlorine reacts with an aqueous solution of potassium bromide to form liquid bromine and an aqueous solution of potassium chloride. B) Solid aluminum reacts with solid iodine to produce solid aluminum iodide. C) Solid magnesium reacts with an aqueous solution of hydrochloric acid to form an aqueous solution of magnesium chloride and bubbles of hydrogen gas. 2) A) Which can be changed when balancing a chemical equation: the coefficients or the subscripts? B) Why? 3) A) Why does each chemical reaction have many possible balanced equations? B) Of all possible balanced equations, which is preferred? 4) Explain what each of the following symbols (underlined) represents: CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2 H 2 O (g) 5) A) When balancing the following chemical equation, which substance should you start with? B) Why? C) Balance the equation. C 2 H 5 OH (l) + O 2 (g) CO 2 (g) + H 2 O (g)

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15 Chemistry Name Hour Assignment 7.4 Chapter Review (2 pages) 1) If a piece of blackboard chalk is heated strongly, the mass of the chalk decreases substantially, and the chalk is converted into a fine powder. What evidence is there for a chemical reaction having taken place when the chalk is heated? 2) The substances present before a chemical reaction takes place are called the, and the substances present after the reaction takes place are called the. 3) In an ordinary chemical reaction, are neither created nor destroyed. 4) The notation of (g) after a substance s formula indicates it exists in the state. 5) In a chemical equation for a reaction, the notation (aq) after a substances formula means that the substance is. Write the unbalanced chemical reaction from each of the following descriptions. 6) If calcium carbonate is heated strongly, carbon dioxide gas is driven off, leaving a residue of calcium oxide. 7) If a sample of pure hydrogen gas is ignited very carefully, the hydrogen burns gently, combining with oxygen gas of the air to form water vapor. 8) Silver (I) oxide may be decomposed by strong heating into silver metal and oxygen gas. 9) Elemental boron is produced in one industrial process by heating diboron trioxide with magnesium metal also producing magnesium oxide.

16 10) When balancing a chemical equation, one must never change the of any reactant or product. 11) After balancing a chemical equation, we ordinarily make sure that the coefficients are the possible. 12) Balance each of the following chemical equations. A) CaF 2 (s) + H 2 SO 4 (aq) CaSO 4 (s) + HF (g) B) KBr (s) + H 3 PO 4 (aq) K 3 PO 4 (aq) + HBr (g) C) TiCl 4 (l) + Na (s) NaCl (s) + Ti (s) D) K 2 CO 3 (s) K 2 O (s) + CO 2 (g) E) SiI 4 (s) + Mg (s) Si (s) + MgI 2 (s) F) MnO 2 (s) + Mg (s) Mn (s) + MgO (s) G) Ba (s) + S 8 (s) BaS (s) H) NH 3 (g) + Cl 2 (g) NH 4 Cl (s) + NCl 3 (g) I) Ba(NO 3 ) 2 (aq) + Na 2 CrO 4 (aq) BaCrO 4 (s) + NaNO 3 (aq) J) C 2 H 5 OH (l) + O 2 (g) CO 2 (g) + H 2 O (l) K) CaC 2 (s) + H 2 O (l) Ca(OH) 2 (s) + C 2 H 2 (g)