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Chemical Reactions & Chemical Equations

Chemical Reactions & Chemical Equations. Chemical Reactions. Chemical Change. A process involving a substance or substances changing into a new substance or substances. Chemical Reactions. Evidence of a chemical reaction. Chemical Reactions. Evidence of a chemical reaction.

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Chemical Reactions & Chemical Equations

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  1. Chemical Reactions&Chemical Equations

  2. Chemical Reactions Chemical Change A process involving a substance or substances changing into a new substance or substances

  3. Chemical Reactions Evidence of a chemical reaction

  4. Chemical Reactions Evidence of a chemical reaction 1) A permanent color change 2) A gas is produced 3) Energy is exchanged 4) A precipitate is produced

  5. Chemical Equations A statement using chemical formulas to describe the identities and relative amounts of reactants and products involved in the chemical reaction

  6. Reactant(s)  Product(s)

  7. MgCO3 MgO + CO2

  8. MgCO3 CO2 + MgO

  9. Phases of Components (s) = solid (l) = liquid (g) = gas (aq) = aqueous MgCO3(s) MgO (s) + CO2(g)

  10. Physical Change Vs. Chemical Change

  11. Physical Change Chemical Change

  12. Physical Change Chemical Change Phase Changes Dissolving Mixing Breaking Separating Filtering Rearrange Atoms New Substances form

  13. Did a chemical change occur? • Permanent Color Change Occurs • Precipitate Formed • Gas is Released • Energy is Exchanged – Temperature

  14. Chemical Reaction Demonstration • Permanent Color Change CuSO4(Aq) + Zn (s) ZnSO4 (Aq) + Cu (s) Blue Gray Clear Black The Zn and Cu are Switching, this is known as a single replacement Reaction. • Gas is Produced HCl (l) + Zn (s) ZnCl (Aq) + H2 (g) • Energy is Exchanged Mg (s) + O2(g) MgO (s) Rapid Oxidation • Precipitate is Formed Pb(NO3)2(Aq) + K2CrO4(Aq) KNO3(Aq) + PbCrO4(s) Clear Bright Yellow

  15. Practice Exercise #1 • Define Chemical Reaction • How do we know a chemical reaction has taken place? • What is a Chemical Equation and Why do we use them? • What are the initial constituents of a chemical reaction? What are the end products called? • What do the following symbols stand for? s l g aq

  16. Types of Chemical Equations

  17. Synthesis • Putting things together • Also known as Direct Combination. 2 Na + Cl2 = 2 NaCl 4 Al + 3 O2 = 2 Al2O3

  18. Decomposition • Breaking things down/Taking apart • AKA Analysis 2 KClO3 = 2 KCl + 3 O2 3 MnO2 = Mn3O4 + O2

  19. Single Replacement • Replacing one element in a compound with another element. 2 Al + 6 HCl = 2 AlCl3 + 3 H2 2 NaBr + Cl2 = 2 NaCl + Br2

  20. Double Replacement • Switching one element from a compound with another element from a different compound. 2 AgNO3 + MgCl2 = 2 AgCl + Mg(NO3)2 HCl + NaOH = NaCl + H2O

  21. Others • Combustion • Rapid Oxidation • XXXX + O2 CO2 + H2O • Oxidation • Add Oxygen (Combustion) • Reduction • Acid – Base Neutralization • Etc……

  22. HW • Due Monday • Read & outline page 249-255

  23. Exothermic Reactions • Release or give off heat. • Heat is a byproduct of the reaction. • Temperature increases as the bonds between products are formed. • Examples • Combustion, Respiration, Oxidation

  24. Endothermic Reactions • Take in or absorb Heat from the surroundings. • Temperature decreases as the reaction progresses. • Heat is used to break bonds of reactants. • Decomposition or Analysis Reactions

  25. Oxidation • Removing Electrons

  26. Reduction • Adding Electrons

  27. Rate of Reaction • Reactions occur at different speeds. • The time it takes for reactants to become products.

  28. Catalysts • They speed up reactions without being affected themselves. • They stay the same • Enzymes in living organisms. • Lowers activation energy • The amount of energy needed to start a reaction.

  29. Speeding Up Reactions • Temperature, Energy, Pressure, Surface Area, Concentration, Collisions, Catalyst.

  30. Measuring Rates of Reactions • Measure Reactants • Measure Products

  31. BalancingChemical Equations

  32. Reactant(s) Product(s)

  33. Phases of Components (s) = (l) = (g) = (aq) = MgCO3(s) MgO (s) + CO2(g)

  34. 1 MgCO3(s) 1 MgO (s) + 1 CO2(g)

  35. Reactants Products 1 MgCO3(s) 1 MgO (s) + 1 CO2(g)

  36. 5 atoms 5 atoms 1 MgCO3(s) 1 MgO (s) + 1 CO2(g)

  37. H2 + O2 H2O

  38. H2 + H2 + O2 H2O + H2O 2 H2 + 1 O2 2 H2O

  39. H2 + H2 + O2 H2O + H2O 2 H2 + 1 O2 2 H2O

  40. Ca + Cl2 CaCl2

  41. Na + Cl2 NaCl

  42. Fe2O3 Fe + O2

  43. AgNO3 + NaCl  NaNO3 + AgCl

  44. FeS2 + O2 Fe2O3 + SO2

  45. 4 FeS2 + 11 O2 2 Fe2O3 + 8 SO2

  46. NH4OH + Ni(NO3)2 NH4NO3 + Ni(OH)2

  47. NH4OH + Ni(NO3)2 NH4NO3 + Ni(OH)2

  48. Na2CO3 + Fe(NO3)3 Fe2(CO3)3 + NaNO3

  49. Na2CO3 + Fe(NO3)3 Fe2(CO3)3 + NaNO3 3 Na2CO3 + 2 Fe(NO3)3  Fe2(CO3)3 + 6 NaNO3 Balanced!!!

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