Honors Chemistry - Unit 7 Chapter 11 Chemical Reactions Important Dates: Diatomics, Reaction Symbols, Balancing Quiz: January 4 th Unit 7 UT Quest (2 parts): Due11:58pm on January 8 th Unit 7 Packet - Page 1 of 12 Reaction Types Quiz: January 5 th Test: January 9 th *Optional UT Quest: Due online at 11:58pm on January 8 th ; work is due on January 9 th before test. VOCABULARY 1) chemical reaction 2) reactants 3) products 4) single displacement 5) double displacement 6) decomposition 7) synthesis (composition) 8) combustion 9) subscript 10) coefficient 11) activity series OBJECTIVES: Be able to balance chemical equations using coefficients. Be able to identify and write the five basic types of equations: single displacement, double displacement, synthesis, decomposition and combustion. Be able to use correct notation in equations (such as state symbols). Be able to identify the seven diatomic molecules and use them correctly in equations. Be able to use the activity series to write equations SYMBOLS USED IN CHEMICAL EQUATIONS State symbols (after formula) s, l, g or aq (book uses cr for crystalline solid) up arrow ( ) gas down arrow ( ) ppt reversible rxn squiggly line above arrow = electric current or with e - as shown below above arrow = heat temp, pressure may be written above arrow catalyst may be written below or above arrow
CHEMICAL EQUATIONS AND REACTIONS Unit 7 Packet - Page 2 of 12 Chemical Equation: represents with symbols and formulas the reactants and products Reactants yields Products Fe2O3 + 2 Al 2 Fe + Al2O3 Equations must: Represent known facts all reactants and products must be included Contain correct formulas Coefficients: numbers in front of compounds/elements Represents the number of moles Subscripts: numbers in the formulas They are never changed when balancing a chemical equation! Symbols used in equations (see page 1) WRITING AND BALANCING EQUATIONS Diatomic molecules: Occur in pairs in their natural state (when they are alone and not ionic, not in compounds) Notice there are 7 of these and they make a 7 shape on the PT!! Also: Br I Cl H O F BALANCING EQUATIONS: When writing equations you must satisfy the law of conservation matter (matter can not be created or destroyed) Therefore we must have the same type and number of each atom on each side of the equation. 1. Start with a word equation (or an unbalanced chemical equation) 2. If a word equation, convert to a formula equation (don t forget the diatomic molecules!) 3. Balance with coefficients: balance each atom one at a time balance polyatomic ions on each side of the equation as one unit balance H and O last (they often appear in more than one compound) 4. Check; if coefficients are not the lowest possible; reduce down.
*****Remember NEVER change subscripts***** Examples: Unit 7 Packet - Page 3 of 12 1. SO2 (g) + O2 (g) SO3 (g) 2. Fe2O3 (s) + H2 (g) Fe (s) + H2O (l) 3. AgNO3 (aq) + CaCl2 (aq) Ca(NO3)2 (aq) + AgCl (s) also ( ) 4. liquid water breaks down into hydrogen gas and oxygen gas 5. methane gas (CH4) + oxygen gas makes carbon dioxide gas + water vapor
Unit 7 Packet - Page 4 of 12
REACTION TYPES Unit 7 Packet - Page 5 of 12 1. Synthesis: (or composition): 2 or more substances combine to form 1 new substance Ex s: A + X AX 2. Decomposition: A single substance produces 2 or more simpler substances Ex s: AX A + X Electrolysis: Ex: 3. Single Displacement (Replacement): 1 element replaces a similar element in a cmpd A + BX AX + B Ex s: Hint: In reactions write water as HOH.
Unit 7 Packet - Page 6 of 12 4. Double Displacement (Replacement): The ions of 2 compounds switch places to form 2 new compounds. AX + BY AY + BX *often one of the new compounds will be a precipitate Ex s: 5. Combustion: When a substance combines with oxygen releasing a large amount of energy in the form of light and heat. Often combustions involve a hydrocarbon : compound containing C and H Ex. CxHy + O2 CO2 + H2O Practice: ID, Write & Balance the following equations: 1. C2H4 + O2 2. lithium and sulfuric acid 3. O2 + Ca 4. PbCl4 + Al(NO3)3 5. CaCl2
Unit 7 Packet - Page 7 of 12
Unit 7 Packet - Page 8 of 12
Activity Series Unit 7 Packet - Page 9 of 12 1. What is the activity series? 2. Where are the most active elements found in the series? Activity Series Practice (Use the series for single displacement reactions or synthesis reactions with oxygen): I. Based on the activity series of metals and halogens, circle the element within each pair that is more likely to replace the other in a compound? K and Na Al and Ni Bi and Cr Cl and F Cl and I Fe and Sr I and F Au and Ag II. Using the activity series of metals and halogens, predict whether each of the possible reactions listed below will occur. For the reactions that will occur, write the products and balance the equation: Ni(s) + CuCl2(aq) Zn(s) + Pb(NO3)2(aq) Cl2(g) + KI(aq) Cu(s) + FeSO4(aq) Ba(s) + H2O(l) III. Use the activity series to predict whether each of the following synthesis reactions will occur, and write the chemical equations for those predicted to occur: Ca(s) + O2(g) Ni(s) + O2(g) Au(s) + O2(g)
UNIT 7 PRACTICE Unit 7 Packet - Page 10 of 12 Balance and ID the following reactions: 1. K3PO4 + HCl KCl + H3PO4 2. Na + HNO3 NaNO3 + H2 3. S + O2 SO3 4. Ca(ClO3)2 CaCl2 + O2 5. C2H12 + O2 CO2 + H2O 6. potassium iodide + lead(ii) nitrate potassium nitrate + lead(ii) iodide 7. iron(iii) oxide + carbon carbon monoxide + iron 8. mercury(ii) oxide mercury + oxygen 9. calcium + aluminum chloride calcium chloride + aluminum 10. mercury(ii) nitrate + sodium carbonate sodium nitrate + mercury(ii) carbonate 11. calcium phosphate + aluminum sulfate calcium sulfate + aluminum phosphate 12. rubidium + acetic acid rubidium acetate + hydrogen 13. Zn + H2SO4 ZnSO4 + H2
14. sodium and bromine yield sodium bromide Unit 7 Packet - Page 11 of 12 15. Cl2 + KI KCl + I2 16. HNO3 + LiOH H2O + LiNO3 17. C3H8 + O2 CO2 + H2O 18. zinc + hydrochloric acid zinc chloride and hydrogen gas 19. potassium hydroxide heated yields potassium oxide and water 20. magnesium and water produce magnesium hydroxide and hydrogen gas Predict the products and write the complete balanced equations: 1. tin(ii) and copper(ii) sulfate 2. calcium and iodine 3. magnesium and sulfuric acid 4. sodium carbonate and hydrochloric acid 5. iron(ii) chloride electrolyzed
6. lithium oxide and water Unit 7 Packet - Page 12 of 12 7. The combustion of C2H4 8. magnesium chloride + manganese(iii) nitrate 9. hydrogen gas + oxygen gas 10. strontium metal + copper(ii) nitrate 11. copper(ii) oxide + sulfuric acid 12. nitrogen gas + lithium metal 13. C4 H8 + O2 14. copper(ii) nitride (heated) 15. potassium metal + water