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Chemical Reactions

Chemical Reactions. Chemical Reactions Objectives. 1. Classify and name compounds in chemical reactions 2. Describe chemical reactions in word and chemical equations . 3. Balance chemical equations based on the Law of Conservation of Mass.

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Chemical Reactions

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  1. Chemical Reactions

  2. Chemical Reactions Objectives 1.Classify and name compounds in chemical reactions 2.Describe chemical reactions in word and chemicalequations. 3.Balance chemical equations based on the Law of Conservation of Mass. 4.Identify and classify types of chemical reactions and energy changes involved. 5.Predictproducts and energy changes in a chemical reaction. 6.Identify and testfactors that affect the rate of chemical reactions.

  3. Chemical Reactions What is a chemical reaction? • Use your background knowledge to explain what a chemical reaction is. • Think about chemical changes you have observed in your surroundings. • Think about chemical changes on an atomic level.

  4. Chemical Reactions Substances chemically interact to form different substances. A substance can be an element or a compound. Chemical bonds are broken and created. Example: Iron chemically reacts withOxygento produce Iron(II) Oxide

  5. Chemical Equations Fe + O2 ------> FeO Reactants: Starting substances. Chemically interact with one another. Usually located to the left of the arrow. Products: Ending substances. Substances formed from the chemical reaction. Usually located to the right of the arrow.

  6. Chemical Equations Fe(s) + O2 (g) ------> FeO (s) (s)= substance in solid state (g)= substancein gaseous state (l)= substance in liquid state (aq)= substance dissovled in water. (aqueous solution)

  7. Chemical Reactions Fe(s) + O2 (g) ------> FeO (s) • Are atoms destroyed or created during a chemical reaction? • No, they are just rearranged to produce new substances.

  8. Law of Conservation Of Mass Matter is not created or destroyed. Matter is just rearranged. (mass of reactants = mass of products) That is why it is important to balance chemical equations.

  9. Conservation of Mass Lab • Observe the conservation of mass lab, to understand why it is important to balance chemical equations.

  10. Balancing Chemical Equations 2Fe(s) + O2 (g) ------> 2FeO (s) Balancing Chemical Equations: • Add coefficients in front of substances, do NOT change subscripts. 2. First balance elements that only appear once on each side of the equation.

  11. Balancing Chemical Equations

  12. Chemical Reactions Bell Ringer 1. N2 (g) + H2(g) --------> NH3(g) • What is the chemical name of one of the reactants? b. What is the chemical name of the product? c. What state of matter is all the substances in this reaction? d. Balance the chemical equation if needed.

  13. Balancing Chemical Equations

  14. Types of Chemical Reactions 1. Synthesis (A+ B ----> AB) 2. Decomposition (AB------> A + B) 3. Single Replacement (A+ BC ---> B + AC) 4. Double Replacement (AB + CD ---> CB + AD) 5. Combustion (CxHx + O2 ----> CO2 + H2O) 6. Neutralization (Acid + Base--> H2O + Salt)

  15. Chemical Reactions Objectives Identify and classify types of chemical reactions. 2. Identify energy changes involved with chemical reactions. 3. Predict products and energy changes in a chemical reaction.

  16. Synthesis (Combination) Reaction 2 or more substances chemically combine to form a single substance. A + B ---> AB + energy Energy released into surroundings is more than energy absorbed by the system. ( Energy of surroundings > Energy of system)

  17. Decomposition Reaction A compound breaks down into simpler substances. AB + energy ----> A + B Energy of system > Energy of surroundings Why?

  18. Single Replacement Reaction An element replaces another element in a compound. A + BC --------> B + AC + energy Energy of surroundings > Energy of system

  19. Double Replacement Reaction Exchange of cations between two compounds. AB + CD + energy ----> CB + AD + more energy Energy of Surrounding > Energy of System

  20. Combustion Reaction Fuel (hydrocarbons) reacts with oxygen to produce predictable substances and energy. CxHx + O2 ----> CO2 + H2O + ENERGY Energy of Surroundings > Energy of System

  21. Neutralization Acid and Base react to produce predictable products. Changes the pH to 7 (neutral). Acid + Base -------> H2O + Salt Salt:An ionic compound. The cation comes from the base and the anion from the acid.

  22. Class Reminders: • Acid Rain Article (15pts.) • Balance Chemical Equations Worksheet (10pts.) (balance and classify equations) • Word Equation Worksheet (10pts.) *3rd Quarter Ends: March 8th*

  23. Chemical Reaction Lab Purpose: • Perform and observe types of chemical reactions. • Determine reactants and predict products. • Classify chemical reactions. • Balance chemical reactions. • Write a formal lab report

  24. Chemical Equations to Lab

  25. Types of Chemical Reactions 1. Synthesis (A+ B ----> AB) 2. Decomposition (AB------> A + B) 3. Single Replacement (A+ BC ---> B + AC) 4. Double Replacement (AB + CD ---> CB + AD) 5. Combustion (CxHx + O2 ----> CO2 + H2O) 6. Neutralization (Acid + Base--> H2O + Salt)

  26. Chemical Equations to Lab Just need to check and see if they are balanced. • Mg + O2 ------> • Mg + HCl ----> • (NH4)2(CO3) -----> NH3 + CO2 + H2O • Ca(CO3) + HCl ----> CaCl2 + H2O + CO2 • Zn + CuCl2 ----> • CuCl2 + Na3(PO4) ---> • HCl + Na(OH) ----> H2O + NaCl • C2H6O + O2 ----->

  27. Chemical Reaction Review What are the coefficients that will balance the chemical equation below? AlCl3 + Na(OH) ----> Al(OH)3 + NaCl 1,3,1,3 3,1,3,1 1,1,1,3 1,3,3,1 What type of chemical reaction is in question 1? Predict the product and balance if needed: Ba (s) + O2 (g) ---------->

  28. Balancing and Classifying Chemical Reactions

  29. Chemical Equations to Lab Just need to check and see if they are balanced. • Mg + O2 ------> MgO • Mg + HCl ----> MgCl + H2 • (NH4)2(CO3) -----> NH3 + CO2 + H2O • Ca(CO3) + HCl ----> CaCl2 + H2O + CO2 • Zn + CuCl2 ----> ZnCl2 + Cu • CuCl2 + Na3(PO4) ---> Cu3(PO4)2 + NaCl • HCl + Na(OH) ----> H2O + NaCl • C2H6O + O2 -----> CO2 + H2O

  30. Conclusion Needs to include the following: Identify and explain the types of reactions obsvd. ? Which reaction(s) did you like the best and why? Based on data section explain which reactions were exothermic and endothermic. What did you learn from this lab?

  31. Predicting Products in a Chemical Reaction • Ca + N2 --------> ? b. Cu2S -------> ? • NaBr + F2 ------> ? • CH4 + O2 ----->

  32. Balancing and Classifying Equations Quiz Types of Chemical Reactions 1. Synthesis 2. Decomposition 3. Single Replacement 4. Double Replacement 5. Combustion 6. Neutralization

  33. Predicting Products • Check my webpage for correct chemical formulas prior to balancing.

  34. Predicting Single Replacement Reactions • An Activity Series can help us predict if a single replacement reaction will take place.

  35. Activity Series Lab Hypothesis

  36. Activity Series Lab • Complete conclusion • Complete Post Lab Questions

  37. Activity Series Lab • Using the Activity Series Table, predict whether the following single replacement reactions would occur: • Li + MgCl b. Hg + Na3P c. Pb + HF

  38. Predicting Single Replacement Reactions An Activity Series can help us predict if a single replacement reaction will take place.

  39. Activity Series Lab Complete conclusion Complete Post Lab Questions

  40. Chemical Reaction Study Guide Changes • Vocabulary words: Thermochemistry 10. HgO + energy ------> Hg + O2 11. Fe + F2 ----------> FeF3 + energy • CH4 + O2 ---------> CO2 + H2O + energy • K(OH) + H3(PO4) -------> 18. Omit last word equation. 

  41. Chemical Reaction Review • What are the coefficients that will balance the chemical equation below? AlCl3 + Na(OH) ----> Al(OH)3 + NaCl • 1,3,1,3 • 3,1,3,1 • 1,1,1,3 • 1,3,3,1 • What type of chemical reaction is in question 1? • Predict the product and balance if needed: BaS + Mg ---------->

  42. Thermochemistry Energy changes that occur within reactions. Endothermic Reactions Exothermic Reactions

  43. Exothermic Reaction Energy absorbed < Energy released. The chemical reaction becomes cooler and its surroundings gets warmer. Energy is on the product side. C8H18 + O2 -------> CO2 + H2O + energy

  44. Endothermic Reactions Energy absorbed > Energy released Chemical reaction gets warmer and its surroundings gets cooler. Energy is on the reactant side. Ex. Photosynthesis

  45. Chemical Reaction Energy Diagram

  46. Chemical Reaction Energy Diagram • Activation Energy (Ea): The amount of kinetic energy • needed to be absorbed from the surroundings for the • chemical reaction to occur. H : The amount of kinetic energy released into the into the surroundings.

  47. Chemical Reaction Energy DiagramExothermic Reaction

  48. Chemical Reaction Energy DiagramEndothermic Reaction Activation Energy

  49. Chemical Reactions Objectives 1.Classify and name compounds in chemical reactions 2.Describe chemical reactions in word and chemicalequations. 3.Balance chemical equations based on the Law of Conservation of Mass. 4.Identify and classify types of chemical reactions and energy changes involved. 5.Predict products and energy changes in a chemical reaction. 6.Identify and test factors that affect the rate of chemical reactions. (Chpt. 18.1)

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