Honors Chemistry - Unit 7 Chapter 11 Chemical Reactions

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1 Honors Chemistry - Unit 7 Chapter 11 Chemical Reactions Vocab Assignment Due: Unit 7 Packet - Page 1 of 15 UT Quest(s): Quiz on Diatomic Molecules & Balancing: Prediction Quiz : Test Date: VOCABULARY Assignment 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 (brief descriptions and table listed below) State symbols (after formula) s, l, g or aq (book uses cr for crystalline solid) up arrow ( ) gas down arrow ( ) ppt ßà reversible rxn squiggly line above arrow = electric current or with e - as shown below Δ above arrow = heat temp, pressure may be written above arrow catalyst may be written below or above arrow

2 CHEMICAL EQUATIONS AND REACTIONS Unit 7 Packet - Page 2 of 15 Chemical Equation: represents with symbols and formulas the reactants and products Example: Reactants yields Products (many other words can be used here) 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 are on your objective sheet! 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!!!!! Memorize!! (quiz): Writing & Balancing Equations l Diatomic molecules occur in pairs in their natural state (when they are alone; not in compounds) I 2, Br 2, Cl 2, F 2, O 2, N 2, H 2 (*Quiz*) I Bring Clay For Our New House or His Brown Clown Found No Oranges Inside

3 Unit 7 Packet - Page 3 of 15 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. BALANCING EQUATIONS: 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: 1. P (s) + O2 (g) à P4O10 (s) 2. SO2 (g) + O2 (g) à SO3 (g) 3. Fe2O3 (s) + H2 (g) à Fe (s) + H2O (l)

4 Unit 7 Packet - Page 4 of AgNO3 (aq) + CaCl2 (aq) à Ca(NO3)2 (aq) + AgCl (s) also ( ) (contains polyatomic ions!) 5. liquid water breaks down into hydrogen gas and oxygen gas 6. methane gas + oxygen gas makes carbon dioxide gas + water vapor You try: 1. solid calcium oxide reacts with liquid bromine to make solid calcium bromide and oxygen gas 2. Ba(NO3)2 + PbO2 à BaO + Pb(NO3)4

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9 BALANCING CHEMICAL REACTIONS Unit 7 Packet - Page 9 of 15 Balance the following reactions: 1. K3PO4 + HCl à KCl + H3PO4 2. Na + HNO3 à NaNO3 + H2 3. S + O2 à SO3 4. Ca(ClO3)2 à CaCl2 + O2 5. C2H12 + O2 à CO2 + H2O 6. Potassium iodide + lead (II) nitrate à potassium nitrate + lead (II) iodide 7. Iron (III) oxide + carbon à carbon monoxide + iron 8. Mercury (II) oxide à mercury + oxygen 9. Calcium + aluminum chloride à calcium chloride + aluminum 10. Mercury (I) nitrate + sodium carbonate à sodium nitrate + mercury (I) carbonate 11. Potassium bromide + aluminum nitrate à potassium nitrate + aluminum bromide 12. Calcium phosphate + aluminum sulfate à calcium sulfate + aluminum phosphate 13. Rubidium + acetic acid à rubidium acetate + hydrogen

10 Equation Writing Balance and ID the following rxns: Unit 7 Packet - Page 10 of Zn + H2SO4 à ZnSO4 + H2 2. Na + Br2 à NaBr 3. H2O à H2 + O2 4. Cl2 + KI à KCl + I2 5. HNO3 + LiOH à H2O + LiNO3 6. C3H8 + O2 à CO2 + H2O 7. Sodium + iodine à sodium iodide 8. Zinc + hydrochloric acid à zinc chloride and hydrogen gas 9. Potassium hydroxide heated yields potassium oxide and water 10. Magnesium and water produce magnesium hydroxide and hydrogen gas Reaction Prediction 1. Tin (II) and copper (II) sulfate 2. Iron (III) nitrate and sodium chromate 3. Calcium and iodine 4. Magnesium and sulfuric acid 5. Calcium oxide electrolyzed 6. Carbon and oxygen 7. Sodium carbonate and hydrochloric acid 8. Iron (II) sulfide electrolyzed 9. Platinum (II) and lead (II) nitrate 10. Lithium oxide and water 11. C2H4 + O2

11 Unit 7 Packet - Page 11 of 15 WRITING CHEMICAL EQUATIONS Write balanced equations for the following reactions after identifying the type of reaction. 1. aluminum sulfate + calcium phosphate 2. magnesium chloride + manganese (III) nitrate 3. Hydrogen gas + oxygen gas 4. Strontium metal + copper (II) nitrate 5. copper (II) oxide + sulfuric acid 6. nitrogen gas + lithium metal 7. C4 H8 + O2 8. sodium bromide + oxygen gas 9. copper (II) nitride (heated) 10. potassium metal + water 11. C3 H8 + oxygen gas 12. ammonium sulfate + sodium chloride 13. NiO + S

12 REACTION TYPES Unit 7 Packet - Page 12 of Synthesis: (or composition): 2 or more substances combine to form 1 new substance Ex s: A + X à AX 2. Decomposition: A single substance produces 2 or more simpler substances Ex s: AX à A + X Electrolysis: Ex:

13 3. Single Displacement (Replacement): 1 element replaces a similar element in a cmpd Unit 7 Packet - Page 13 of 15 A + BX à AX + B Ex s: Hint: In reactions write water as HOH. 4. Double Displacement (Replacement): The ions of 2 cmpds switch places to form 2 new cmpds. AX + BY à AY + BX *often one of the new cmpds will be a ppt. Ex s:

14 Unit 7 Packet - Page 14 of 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 : cmpd containing C and H Ex. CxHy + O2 à CO2 + H2O Group Practice: ID, Write & Balance the following equations: 1. C2H4 + O2 à 2. Barium + Copper (II) chloride 3. O2 + Ca 4. PbCl4 + Al(NO3)3 5. CaCl2

15 Activity Series Pg 333 Unit 7 Packet - Page 15 of 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) à Zn(s) + Pb(NO3)2(aq) à Cl2(g) + KI(aq) à Cu(s) + FeSO4(aq) à Ba(s) + H2O(l) à 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) à Ni(s) + O2(g) à Au(s) + O2(g) à