1 / 51

Chemical Reactions and Equations

Chemical Reactions and Equations. Chapter 8. Chemical reactions…. Process by which one or more substances are described by a. 4 Signs of a Chemical Reaction:. Evolution of _________ and ________________ 2. Production of ______________

kpagel
Download Presentation

Chemical Reactions and Equations

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chemical Reactions and Equations Chapter 8

  2. Chemical reactions…. • Process by which one or more substances are • described by a

  3. 4 Signs of a Chemical Reaction: • Evolution of _________ and ________________ 2. Production of ______________ 3. Formation of a _____________________(solid produced as a result of a chem rxn in a sol’n) 4. _____________________change

  4. Chemical equation • Represents the identities and relative amounts of the reactants and products in a chemical reaction • (NH4)2Cr2O7(s) ---> N2(g) + Cr2O3(s) + 4H2O(g) Characteristics: • represents the _______________________________ • contains correct _________________ for the reactants & products • satisfies the law of ____________________________ (same # and kind of atoms on both sides of the equation)

  5. (NH4)2Cr2O7(s)---> N2(g) + Cr2O3(s) + 4H2O(g) • Formula equation: uses symbols/formulas to represent the reactants and products • Reactants • products • coefficient (understood to be “1” if no # appears • symbols (p.246)

  6. ammonium dichromate --> nitrogen + chromium(III) oxide + water • Word equation: (previous ex.) • only fulfills ONE characteristic of a chem eq (____________________________________) • 1st step in writing a balanced chemical equation

  7. Steps to write a balanced chemical equation: 1. Write the word equation. 2. Convert the word equation into a formula equation. 3. Include symbols, where known. 4. Balance the equation. NEVER CHANGE A SUBCRIPT IN BALANCING EQUATIONS!

  8. Cu + H2SO4 CuSO4 + SO2 + H2O Cu H S O Cu + H2SO4 CuSO4 + SO2 + H2O

  9. SiF4 + H2O  H2SiF6 + H2SiO3 Si F H O SiF4 + H2O  H2SiF6 + H2SiO3

  10. Solutions of lead(II) nitrate and sodium hydroxide react to produce a lead(II) hydroxide precipitate and an aqueous solution of sodium nitrate.

  11. Solid rubidium oxide reacts with water to produce an aqueous solution of rubidium hydroxide.

  12. Lithium reacts with a hydrochloric acid solution to produce an aqueous solution of lithium chloride and hydrogen.

  13. In the presence of an electrical current, sodium hydroxide can be produced from the reaction of a sodium chloride solution with water. Hydrogen and chlorine gases are the other products.

  14. Aluminum sulfate is produced when aluminum hydroxide reacts with sulfuric acid. Water is the other product.

  15. 5 types of chemical reactions: • synthesis (composition) • decomposition • single-replacement (displacement) • double-replacement (displacement) • combustion

  16. Synthesis Reactions • 2 or more substances combine to form a new compound • 2 H2 + O2 2H2O

  17. Reactions of metals with oxygen and sulfur • magnesium metal + oxygen  • barium + sulfur (S8) 

  18. Some metals can form oxides of varying oxidation #: • iron + oxygen  iron(II) oxide • iron + oxygen  iron(III) oxide

  19. Nonmetals can also form oxides • S8(s) + 8O2(g)  8SO2(g) • C(s) + O2(g)  CO2(g) • 2C(s) + O2(g)  2CO(g)

  20. Reactions of metals with halogens • potassium + iodine  • strontium + bromine  • cobalt + fluorine  [cobalt(III) ion forms]

  21. Synthesis reactions with metal oxides • activemetals* oxides + water  hydroxides • calcium oxide + water  • *(see p. 266)

  22. Synthesis reactions with nonmetal oxides • nonmetal oxides + water  oxyacids • sulfur dioxide + water 

  23. Synthesis reaction of metal oxide & nonmetal oxide • calcium oxide + sulfur dioxide 

  24. Decomposition • a single cmpd undergoes a rxn that produces 2 or more simpler substances • H2CO3 H2O + CO2

  25. Decomposition of… • binary cmpds • metal carbonates • metal hydroxide • metal chlorates • acid

  26. Decomposition of binary cmpds • simplest decomposition rxn • decomposition into elements • ELECTROLYSIS: decomp by an electric current • 2 H2O(l)electricity--->

  27. Decomposition of Metal Carbonates • when heated (∆), produce a metal oxide and carbon dioxide gas • CaCO3(s) -∆

  28. Decomposition of Metal Hydroxides • all metals except Gp 1 decomp when heated to produce metal oxides and water • Ca(OH)2(s) -∆ CaO(s) + H2O(g)

  29. Decomposition of Metal Chlorates • when heated, decompose to produce a metal chloride and oxygen • KClO3(s) -∆ 2KCl(s) + 3O2(g)

  30. Decomposition of Acids • Many acids decompose into nonmetaloxides and water • H2SO4(aq) -∆ • H2CO3(aq) 

  31. Single Replacement Reaction • one element replaces a similar element in a cmpd • 2 Al + Fe2O3 Al2O3 + 2 Fe

  32. Single Replacement Reaction of… • a metal in a cmpd by another metal • hydrogen in water by a metal • hydrogen in an acid by a metal • replacement of halogens

  33. Replacement of a metal in a cmpd by another metal • aluminum + lead(II) nitrate  • (p. 266 Al is more reactive than Pb so a spontaneous reaction will occur)

  34. Replacement of H in water by a metal (active) very active metals (i.e. Gp 1) pulls one H from the water • sodium + water 

  35. Replacement of H in water by a metal (less-active) less- active metals reacts with steam and pulls-off both hydrogens from the water • iron + water 

  36. Replacement of H in an acid by a metal more-active metals reacts with some acidic soln’s • magnesium + hydrochloric acid 

  37. Replacement of Halogens • a more reactive halogen will replace a less-active halogen • the higher up in the Gp 17 family, the MORE reactive the halogen • Reactivity: F>Cl>Br>I • chlorine gas + potassium bromide sol’n 

  38. fluorine gas + sodium chloride sol’n  • bromine liquid + potassium chloride sol’n 

  39. Double replacement reactions • ions of 2 cmpds exchange places in an aqueous solution to form 2 new cmpds • ZnBr2 + 2 AgNO3 Zn(NO3)2 + 2 AgBr

  40. Double displacement reactions….. • formation of a precipitate • formation of a gas • formation of water

  41. Formation of a precipitate • one product is insoluble (or just slightly soluble) …see page 427 • potassium iodide + lead (II) nitrate 

  42. Formation of a gas • one product is an insoluble gas and bubbles out • iron(II) sulfide + hydrochloric acid sol’n 

  43. Formation of Water • one of the products yields the molecular cmpd water • hydrochloric acid + sodium hydroxide 

  44. Combustion Reactions • substance reacts with oxygen and releases a large amount of energy (light and heat) • hydrogen + oxygen  water vapor • hydrocarbon + oxygen  carbon dioxide + water

  45. Combustion (burning) of propane: • C3H8(g) + O2

  46. Will cobalt react with sodium chloride? Co(s) + NaCl(aq)  ?

  47. Activity Series • list of elements organized according to the ease with which the elements undergo certain chemical reactions • are at the TOP and can replace a metal in a cmpd found below it in single displacement reactions

  48. Will the following react? IF so, write an equation. • Mn + H2O --30C ? • Cd + O2  • Ag + HCl 

More Related