11 BALANCING CHEMICAL EQUATIONS

Transcription

1 1 11 BALANCING CHEMICAL EQUATIONS Directions:. Label decomposition, synthesis (combination), single displacement, double displacement (or double replacement), combustion reaction or Neutralization (acid/base). Balance the Chemical Equation Reaction Type 1. 2 K + 1 Cl 2 2 KCl COMBINATION 2. SO 2 + O 2 SO 3 3. KClO 3 KCl + O 2 4. CO 2 + C CO 5. H 2 + O 2 H 2 O 6. MgCO 3 MgO + O 2 7. H 2 O + Cs CsOH + H 2 8. Fe 2 O 3 + Al Fe + Al 2 O 3 9. PbCl 2 + Li 2 SO 4 PbSO 4 + LiCl 10. NaOH + H 2 SO 4 Na 2 SO 4 + H-OH 12. Pb(OH) 2 + HCl PbCl 2 + H-OH 13. Na 2 CO 3 + HCl H 2 CO 3 + NaCl 14. AgNO 3 + Cu Ag + Cu(NO 3 ) CH 4 + O 2 CO 2 + H 2 O 16. C 2 H 6 + O 2 CO 2 + H 2 O 17. C 3 H 8 + O 2 CO 2 + H 2 O 18. C 4 H 10 + O 2 CO 2 + H 2 O 19. C 5 H 12 + O 2 CO 2 + H 2 O Bonus: Don t unless given permission. Use decimal method if needed, for example 1.5 O C 7 H 5 N 3 O 6 + O 2 CO 2 + H 2 O + N 2 1

2 Equations must be balanced How To Write & Balance Chemical Reactions Atoms can be neither created nor destroyed in an ordinary chemical reaction, so there must be the same number of atoms on both sides of the equation. These numbers are found in a chemical equation 2 2H 2 + O 2 2H 2 O Subscripts The small numbers to the lower right of chemical symbols. Subscripts represent the number of atoms of each element in the molecule. Coefficients The large numbers in front of chemical formulas. Coefficients represent the number of molecules of the substance in the reaction. Balancing Equations By Inspection 1. Balance Metals 2. Balance Nonmetals 3. Balance Ions 4. Balance Oxygen 5. Balance Hydrogen 6. DOUBLE CHECK DIRECT COMBINATION REACTIONS A + B AB (also called synthesis reactions ) A. In the Haber process, nitrogen gas and hydrogen gas are combined under high temperature and pressure to form ammonia (NH 3 ). B. One of the rare reactions among the noble gasses that have been discovered is the formation of solid xenon tetrafluoride from the combination of xenon and fluorine gas. 2

3 C. Pure magnesium metal is burned to form magnesium oxide, a fine white Powder. 3 D. Sodium metal and chlorine gas react to form table salt. E. Iron nails rust to form ferric oxide. F. Phosphorus is mixed with chlorine gas to form phosphorus pentachloride (PCl 5 ) G. Water is added to ammonia to yield ammonium hydroxide. DECOMPOSITION REACTIONS AB A + B E. Electricity is run through water, liberating oxygen gas and hydrogen gas. F. Hydrogen peroxide decomposes in the presence of a catalyst (manganese), to liberate oxygen gas, leaving only water behind. HYDROCARBON COMBUSTION C n H 2n+2 + O 2 H 2 O + CO 2 Methane CH 4 Hexane C 6 H 14 Ethane C 2 H 6 Heptane C 7 H 16 Propane C 3 H 8 Octane C 8 H 18 Butane C 4 H 10 Nonane C 9 H 20 Pentane C 5 H 12 Decane C 10 H 22 G. Combustion of methane H. Combustion of butane 3

4 I. Combustion of propane 4 SINGLE REPLACEMENT REACTIONS A + BC AB + C J. When Copper metal is added to silver nitrate, pure silver is deposited and a blue solution of copper (I) nitrate remains. K. (find one in the book or internet) L. Lead (II) sulfide is heated in the presence of oxygen to form solid lead (II) oxide and sulfur dioxide gas. DOUBLE REPLACEMENT REACTIONS AB + CD AC + BD M. Solid carbon is added to aluminum oxide in order to form pure aluminum metal and carbon dioxide gas. N. If solutions of potassium chromate and barium chloride are mixed, a bright yellow solid called barium chromate is formed, leaving potassium chloride in solution. O. Hydrochloric acid is added to sodium hydroxide to produce water and sodium chloride. P. (find one in the book or internet) 4

5 5 Name 11 Writing & balancing Chemical Reactions Here are some sample reactions. Can you write the unbalanced reaction? What type of reaction is taking place? (advanced: balance the rx's) 1. sulfur trioxide and water combine to yield sulfuric acid. Date Period 2. lead(ii) nitrate and sodium iodide react to yield lead iodide and sodium nitrate. 3. calcium fluoride and sulfuric acid yield calcium sulfate and Hydrofluoric acid. 4. Sodium metal and chlorine gas yield sodium chloride. 5. ammonia gas, when bubbled into water, will yield ammonium hydroxide. 6. ethane is burned in oxygen to yield carbon dioxide and water. 7. zinc sulfide and oxygen yields zinc oxide and sulfur. 8. Aluminum metal reacts with Calcium oxide to produce calcium metal and aluminum oxide. 9. aluminum hydroxide and sulfuric acid yields water and aluminum sulfate. 10. Silver (I) nitrate reacts with copper metal to yield silver metal and copper (I) nitrate. 11. barium hydroxide and sulfuric acid yield water and barium sulfate. 12. aluminum sulfate and calcium hydroxide react to form aluminum hydroxide and calcium sulfate. 5

6 Combustion of Hydrocarbons A hydrocarbon is formed when a central carbon atom (or chain of carbon atoms) bond with hydrogen atoms. The simplest hydrocarbons are the alkanes, with a general formula of... C n H 2n + 2 For example, what is the formula for an alkane hydrocarbon with 3 carbons? Solution: Fill in the above general formula with the new numbers as follows: C 3 H (2 x 3) + 2 = C 3 H 8 Alkanes are named as follows: n = Formula Name Acronym New Acronym 1 CH 4 methane Mother M 2 ethane eats E 3 propane peanut P 4 butane butter B 5 pentane pizza. P 6 hexane Hence H 7 heptane her H 8 octane office O 9 nonane never N 10 decane dines D Most hydrocarbons, including all the alkanes undergo combustion (burning in oxygen) to form Carbon dioxide and water. For example, write the formula for the combustion of ethane: C 3 H 8 + O 2 CO 2 + H 2 O Now, we just need to balance the reaction. C 3 H 8 + 5O 2 3CO 2 + 4H 2 O COMMON ACIDS Hydrochloric acid HCl Nitric acid HNO 3 Hydrobromic acid HBr Phosphoric acid H 3 PO 4 Hydroiodidic acid HI Citric acid H 3 C 6 H 5 O 7 Hydrofluoric acid HF Carbonic acid H 2 CO 3 Sulfuric acid H 2 SO 4 Formic acid HCO 2 H Acetic acid HCH 3 CO 6 6

7 7 Name Date Period Writing and balancing Chemical Reactions Here are some sample reactions. First write the chemical reaction, then determine the type of reaction taking place. Finally, balance the reaction. 1. Carbon dioxide and water combine to yield carbonic acid. CO 2 + H 2 O H 2 CO 3 2. Carbon disulfide reacts with oxygen to form carbon dioxide and sulfur dioxide. 3. When heated, calcium carbonate yields carbon dioxide and calcium oxide. 4. Calcium fluoride reacts with sulfuric acid to form calcium sulfate and hydrogen fluoride. 5. Lithium oxide reacts with water to form lithium hydroxide. 6. Pentane burns. 7. When water is exposed to electricity, oxygen and hydrogen are formed. 8. Aluminum reacts with iron (II) nitrate to form aluminum nitrate and iron. 9. Hydrochloric acid reacts with ammonium hydroxide. 7

8 10. Sodium reacts with bromine to form sodium bromide Decane burns. 12. When heated, potassium chlorate forms potassium chloride and oxygen. 13. Magnesium burns to form magnesium oxide. 14. Aluminum reacts with fluorine to form aluminum fluoride. 15. Hydrochloric acid reacts with calcium metal to produce calcium chloride and hydrogen gas. Name the following compounds: a. C 3 H 8 b. H 2 PO 4 c. FeCl d. Cu(NO 3 ) 2 e. SCl 5 f. (NH 4 )O g. C 8 H 18 h. Mg(OH) 2 8

9 9 Name Date Period 11 Writing and balancing Chemical Reactions II Name the following compounds: IONIC COVALENT 1. C 6 H HCH 3 CO 2 3. CuCl 4. Al(NO 3 ) 3 5. PF 4 6. NH 4 OH 7. CH 4 8. Fe(OH) 2 Here are some sample reactions. First write the chemical reaction, then determine the type of reaction taking place. Finally, balance the reaction. 9. Sodium metal reacts violently in water to form hydrogen gas and sodium hydroxide. 10. Chlorine gas reacts with magnesium iodide to form magnesium chloride and pure iodine. 11. Iron reacts with copper (II) sulfate to form iron (III) sulfate and pure copper 12. Hydroiodidic acid reacts with calcium hydroxide. 13. Combustion of heptane. 14. Solid iron reacts with chlorine gas to form iron (III) chloride Carbon monoxide burns to form carbon dioxide.

10 10 Predicting Reactions Worksheet 1 Combination Reactions - Predict the product and write balanced reactions for each of the following. 1. Hydrogen burned in oxygen. H 2 + O 2 H 2 O 2. Sodium plus iodine. 3. Calcium burned in chlorine. 4. Carbon burned in oxygen. 5. Hydrogen combined with nitrogen. 6. Sulfur burned in air. 7. Magnesium burned in hydrogen. 8. Zinc plus bromine. 9. Water plus carbon dioxide. 10. Sulfur dioxide plus water. 11. Sodium plus hydrogen. 12. Hydrogen burned in chlorine. Decomposition (decombination) - Predict products (if needed) and write balanced reactions for each: If you need to search the net to find the products, you can do that also with permission. 1. The heating of magnesium carbonate to MgCO 3(s) MgO (s) + CO 2(g) form Magnesium Oxide & Carbon Dioxide. 2. The heating of sodium chlorate to form Sodium Oxide and Dichloro-oxide. 3. The electrolysis of water. 4. The decomposition of calcium carbonate to form Calcium Oxide and Carbon Dioxide. 5. The heated of mercuric oxide. 6. The electrolysis of sodium chloride. 7. Ferric hydroxide heated. 8. Aluminum hydroxide heated. 9. Sodium carbonate heated. 10. Barium hydroxide heated. 11. The electrolysis of calcium bromide. 12. The heating of carbonic acid. 10

11 11 9 IONIC COMPOUND NAMING CHART Directions: Write the formala name of each compound. F - Cl SO 4 CO 3 NO 3 - PO 4 3- CrO 4 2- CH 3 CO 2 3- NH 4 + Ammonium Flouride Ammonium Acetate (vinegar) K+ Na+ Ag Ca 2+ Mg 2+ Ba 2+ Al 3+ Fe 2+ Fe 3+ Iron III Flouride Iron III Phosphate 9 IONIC COMPOUND FORMULA CHART Directions: NH 4 + Write the chemical formula of each compound. Make sure the oxidation number add up to zero. F - Cl - 2- SO 4 2- CO 3 - NO 3 3- PO 4 2- CrO 4 3- CH 3 CO 2 NH 4 F K+ Na+ Ag+ Ca 2+ Mg 2+ Ba 2+ Al 3+ Fe 2+ Fe 3 (PO 4) 2 Fe 3+ FeCl 3 11

12 12 9 IONIC REACTION LAB CHART Directions: 1) Write the entire chemical formula of each anion & cation below to be used (look at NaCl/AgNO 3 ). 2) Put one drop of each chemical on the plastic grid sheet. Record your observations below. Anions Cations! A AgNO 3 B F - Cl - NaCl White ppt SO 4 2- CO 3 2- NO 3 - CaNO 3 No (NR) Reaction PO 4 3- CrO CH 3 CO C D E F G H I J Directions: 1) Pick one reaction which made a Precipitate from each column and write the ionic reaction. 2) Use the solubility rule to determine which product formed the precipitate & which was soluble. 3) Cross out the products which were soluble because they re spectators as reactants & products. column Reactants Products AgNO 3 + NaCl AgCl + NaNO 3 Rule # states that Chlorides are soluble A 2 Ag + +NO Na + +Cl- AgCl +Na + +NO 3 - B C D E F G H I except with Ag, Pb & Hg. Ag + + Cl- AgCl Total ionic equation J 12

13 WORKSHEET ON SINGLE & DOUBLE REPLACEMENT REACTIONS Predict the products. Write formulas & balance each reaction. If there is no reaction, then just put NO RXN. Single Replacement: 1. Zinc + Hydrogen chloride 2. Magnesium + Hydrogen Sulfate 3. Copper (II) chloride + Flourine 4. Silver + Sodium Hydroxide 5. Potassium iodide + Bromine 6. Calcium + Hydrogen hydroxide 7. Iron IV oxide + Hydrogen A + BC B + AC or A + BC C + BA (when A and C are negative ions) Double Replacement: AB + CD AD + CB 1. Barium chloride + Aluminum sulfate 2. Calcium nitride + water 3. Calcium hydroxide + Hydrogen phosphate 4. Hydrogen sulfate + Sodium hydrogen carbonate 5. Calcium hydroxide + Ammonium chloride 6. Potassium iodide + Lead II Nitrate 7. Sodium acetate + Calcium sulfide Complete each word equation, write formulas and balance the reaction equation. Then identify and place the type of reaction (single replacement or double replacement) in the blank provided. 1. Zinc + Silver nitrate 2. Aluminum + Hydrogen chloride 3. Magnesium oxalate + Ammonium carbonate 4. Calcium + Aluminum nitrate 5. Potassium flouride + Lead (II) Nitrate 6. Calcium bromide + Silver nitrate 7. Ammonium phosphate + Barium acetate 8. Sodium chloride + Potassium 9. Magnesium nitrate + ammonium chloride 10. Iron (III) chlorate + calcium 11. Chlorine + Sodium bromide 12. Potassium chloride + Silver nitrate 13. Calcium hydroxide + Hydrogen nitrate 14. Lead II nitrate + Potassium chloride 15. Strontium carbonate + Hydrogen nitrate 16. Gold + Potassium nitrate 17. Zinc + Silver nitrate 18. Aluminum + Copper II sulfate 13 13

14 11-1 Comparing Synthesis and Decomposition Reactions Formative Assessment 1. An equation with the A + B AB format is which of the following types of reaction? a. combustion b. synthesis/combination c. c. decomposition 2. Which of the following reactions is an example of the above unbalanced reactions? a. H 2 + O 2 H 2 O c. CH 4 + O 2 H 2 O + CO 2 b. H 2 O 2 H 2 O+ O 2 d. Na + H 2 O NaOH + H 2 3. Which above reaction in #2 is a decomposition reaction? 4. Which above reaction is a single replacement reaction? 5. Which above reaction is a combustion reaction? Directions - Write the following reactions equation noting the states. For example, note a gas as (g). Then balance the equation by placing coefficients in front of the formula. For example, 2 CO Hydrogen gas reacts with oxygen gas to form water vapor? Score / Chemical Reaction Formative Assessment Approaching 1. Circle the letter of the reactions below that are balanced equations. a. 2PbO 2 PbO + O 2 b. (NH 4 ) 2 CO 3 2NH 3 + H 2 O + CO 2 c. Pb(NO 3 ) 2 + 2NaI PbI 2 + 2NaNO 3 Meets 2. Balance the following equations: a. Fe + O 2 Fe 3 O 4 14 b. C 2 H 6 + O 2 CO 2 + H 2 O Exceeds 3. Write an equation of the chemical reaction when we burned Magnesium in Oxygen. + Score / Writing Equations- Formative Assessment 1. Convert the following unbalanced equation into the written form (See number 2): CH 4 (g) + O 2 (g) H 2 O (g) + CO 2 (g) Methane 2. Convert the following into a balanced chemical equation: Hydrogen peroxide is catalyzed by Manganese IV Oxide decomposes to form water & Oxygen gas. 3. Which is the correct balanced equation for the combustion of Methane? a. CH 4 (g) + O 2 (g) H 2 O (g) + CO 2 (g) c. CH 4 (g) + 2O 2 (g) 2H 2 O (g) + CO 2 (g) b. C 2 H 6 (g) O 2 (g) 3H 2 O (g) + 2CO 2 (g) d. C 3 H 8 (g) + 5O 2 (g) 4H 2 O (g) + 3CO 2 (g) 4. Balance the following equation by filling in the missing numbers and letters. BaO( ) + O 2 ( ) BaO ( ) Score /10 14

15 First Last Name Per 4 11 & 25 Cumulative & Reteaching Score /20 4 Atomic Structure Problem Symbol Isotope Avg Atomic Mass # Atomic Neutrons Electrons Protons Number Name Mass Number = 1. Magnesium? 24.3 = 25? From the above chart, Isotopes of the same element have different: protons, neutrons, electrons 3. Elements are always Identified by the same: protons, neutrons, atomic mass 4. Ions are formed because of a losing or gaining protons, neutrons, none correct 25 Nuclear Chemistry Mass Letter P He Charge Fill missing numbers Reaction type Radioisotope Reactants Reacts To Form Products 7. Beta Decay Oxygen 17 O 1 e + 8. How much material is left after 3 half lives: 100% 50% 25% 12.5% None correct 5&6 Electron Configuration Element Electron Configuration Noble Gas Shorthand Highest Energy Level with Electrons 9. 1s 2 2s 2 2p 6 3s 2 3p In 2s 2, the 2 represents which 3 (column, group, family, period, row or energy level). # electrons in highest level Fission Or Fusion Lewis Dot 7 Ions and Bonding 11. Which 2 have 3 valence electron? (Aluminum, magnesium, Group 1A, Group 3A) 12. Aluminums charge after reacting would be (0, 1+, 2+ 3+) 13. Which formula is correct? (AlCl, MgCl 2, AlCl 3 ) 8 Covalent Bonding 14. What type of bond is Aluminum Chloride? (covalent, ionic, metallic) 9 Naming Type 1 Type II Type III 15. What is the name of MgCl 2? Magnesium Chloride Magnesium II Chloride Manganese Dichloride 16. What is the name of Fe 2 O 3? Iron Oxide Iron III Oxide Di Iron Tri oxide 17. What is the name of Nl 3? Nitrogen Iodide Nitrogen III Iodide Nitrogen Tri iodide 18. From the above, Type I is (alkalis, transitions), Type II is (transitions, non metals) & Type III is (alkalis, nonmetals) 11 Reactions 19. The missing product in the reaction: HCl + Ba(OH) 2 + _ BaCl 2 is: [H OH HBa Cl OH] 20. The above reaction is a: single replacement double replacement combustion 21. To balance the above reaction, the coefficients would be: (1,1,1,1 2,1,2,1 3,1,3,1) 10 Moles grams of Carbon is how many moles: grams of Carbon is how many molecules: 3.01 x x x none correct grams of Hydrogen is how many liters: none correct 25. = Show work for the # 8 above. Corrected by 15

16 11CHEMICAL RXN S 16 / pts First Last Name Per Cornell Question & Ans A + B AB Directions: Make 5 questions & answers that are different Anticipatory Response than the Anticipatory Response 1.Chemical reactions occur 1. only when atoms are joined or rearranged? Y N 2. In the above equation, the the rt. side are reactants? Y N 3. means to produce, to make, or to yield? Y N 4.Skeleton equations are not 2. Balanced? Y N 5. Hydrogen can be written as H in an equation? Y N 6. Catalysts & heat are always written on the arrow? Y N 7. Aqueous (aq), liquid(l) & gas (g) should be written? 3. Anticipatory Response 1. A + B AB is the pattern for a decomposition reaction? Y N 2. H 2 + O 2 H 2 O fits the pattern for synthesis? Y N 3. Photosynthesis is called so 5. because chlorophyll combines CO 2 +H 2 O to makesugar? Y N 4The reverse of #3 when sugar burns is a combustion? Y N 5.Double replacement reactions Involve cations & anions? Y N Summary Section: 4. 16