1 / 34

CH110 Chapter 5 Chemical Reactions

CH110 Chapter 5 Chemical Reactions. Moles Chemical Changes Chemical Equations Types of Reactions Oxidation-Reduction Energy in Chemical Reactions Reaction Rates. The Mole. 2. 1 pair = 1 dozen = 1 mole =. 12. 6.02 x 10 23. 602,000,000,000,000,000,000,000. 1 mol eggs___

bethany
Télécharger la présentation

CH110 Chapter 5 Chemical Reactions

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. CH110 Chapter 5Chemical Reactions • Moles • Chemical Changes • Chemical Equations • Types of Reactions • Oxidation-Reduction • Energy in Chemical Reactions • Reaction Rates

  2. The Mole 2 1 pair = 1 dozen = 1 mole = 12 6.02 x 1023 602,000,000,000,000,000,000,000. 1 mol eggs___ 6.02 x 1023eggs 1 mol Au_______ 6.02 x 1023 Au atoms _____1 mole H2O_____ 6.02 x 1023 H2O molecules

  3. The Mole & Molecular Weight (Mass) 1 mole = MW in g’s 1 mole S = 32 g S 1 mol S_ 32 g S 32 g S 1 mol S 1 mole C = 12 g C 1 mol C 12 g C 12 g C 1 mol C

  4. Molecular Weight (Mass) Find the MW of Glucose; C6H12O6 6 mol C 1 12.0 g C = 1 mol C 72.0 g C 12.0 g H 12 mol H 1 1.0 g H = 1 mol H 96.0 g O 6 mol O 1 16.0 g O = 1 mol O 180.0 g C6H12O6 1 mol C6H12O6

  5. What is Chemistry? • “The study of Matter and its Changes.” Physical Changes= Changes in a Physical Property • Appearance: • melting, freezing, evaporation… • stretching, molding, cutting… Chemical Changes = Changes in a Chemical Property Chemical Composition:

  6. Chemical Changes • Change in the Chemical Composition Examples: Burning of Magnesium Rusting of Iron Decomposing of wood Souring of Milk

  7. Chemical Reactions • Gas formed • Solid precipitate formed • Color change • Temperature Change • Gives heat = exothermic • Gets cold = endothermic

  8. Chemical Reactions • Shows how the Chemical change occurs. Reactants Products  C3H8 + O2 CO2 + H2O + Energy Mg + O2 MgO + Energy Fe + O2 Fe2O3

  9. Chemical equations Chemist’s shorthand to describe a reaction. heat 2 H2 + O2 2 H2O + E (g) (g) (g) • Reactants • Products • The state of all substances (g) (l) (s) (aq) • Any conditions used in the reaction • Same # & type atoms on each side • Law of Conservation of Matter

  10. Balancing Equations Making Hot dogs: How many packages wieners & buns to buy so none is left over. 3 2 24 ___W8 + ___B12 ___WB • Reactants • Products http://www.youtube.com/watch?v=oYIHLUxzRr8

  11. Balancing Equations Na3PO4 + MgCl2Mg3(PO4)2 + NaCl • Reactants • Products 3 1 4 1 2 Na P O Mg Cl 1 2 8 3 1 Step 1: Count atoms of each element on both sides of equation.

  12. Balancing Equations Na3PO4 + MgCl2Mg3(PO4)2 + NaCl • Reactants • Products 3 1 4 1 2 Na P O Mg Cl 1 2 8 3 1 - not balanced - not balanced - not balanced - not balanced - not balanced Step 2: Determine which atoms are not balanced.

  13. Balancing Equations Na3PO4 + MgCl2Mg3(PO4)2 + NaCl • Reactants • Products 3 1 4 1 2 Na P O Mg Cl 1 2 8 3 1 - not balanced - not balanced - not balanced - not balanced - not balanced Step 3: Balance elements with #’s in front of formulas until all balanced. (Never change the formulas!)

  14. Balancing Equations 2 3 1 6 Na3PO4 + MgCl2Mg3(PO4)2 + NaCl • Reactants • Products 3 1 4 1 2 Na P O Mg Cl 1 2 8 3 1 - not balanced 6 6 - not balanced 2 - not balanced 8 - not balanced 3 - not balanced 6 6 • Hints: • Start with a metal in a complex compound, or an element that only appears in one formula. (ie Mg here)

  15. Balancing Equations C2H6 + O2CO2 + H2O • Reactants • Products C H O • Hints: • Start with an element that only appears in one formula on both sides of the equation. • Leave oxygen until last.

  16. Balancing Equations C2H6 + O2CO2 + H2O • Reactants • Products 2 6 2 C H O 1 2 3 Step 1: Count atoms of each element on both sides of equation.

  17. Balancing Equations C2H6 + O2CO2 + H2O • Reactants • Products 2 6 2 C H O 1 2 3 - not balanced - not balanced - not balanced Step 2: Determine which atoms are not balanced.

  18. Balancing Equations 3.5 2 3 C2H6 + O2CO2 + H2O • Reactants • Products 2 6 2 C H O 1 2 3 2 - not balanced - not balanced 6 - not balanced 7 5 7 Step 3: Balance one element at a time with coefficients in front of formulas until all balanced. (Never change the formula!)

  19. Balancing Equations 3.5 2 3 C2H6 + O2CO2 + H2O • Reactants • Products 2 6 2 C H O 1 2 3 2 6 7 5 7 Can’t have 3.5 O2 , so multiply equation by 2!

  20. Balancing Equations 3.5 7 4 6 2 C2H6 + O2CO2 + H2O • Reactants • Products 2 6 2 C H O 1 2 3 4 2 4 12 6 12 14 7 5 7 14 Can’t have 3.5 O2 , so multiply equation by 2!

  21. Types of Chemical Reactions Combustion Complete: C3H8 + 5O2 3CO2 + 4H2O Incomplete: 2C3H8 + 7O2 6CO + 8H2O C3H8 + 2O2 3C + 4H2O

  22. Types of Chemical Reactions Combination A + B  C Decomposition C  A + B Single Replacement: Substitution A + BX B + AX Double Replacement: Metathesis AX + BYBX + AY

  23. Combination Reactions A + B  C Explosion of Hydrogen Balloon 2H2 + O2 2H2O Rusting of Iron 4 Fe + 3 O2 2 Fe2O3 Formation of Acid Rain SO3 + H2O  H2SO4

  24. 2 H2O2 2 H2O + O2 Decomposition Reactions C  A + B Heating Egg Shells CaCO3  CaO + CO2 Blood with peroxide

  25. Single Replacement Reactions A + BX B + AX Iron Deposits on an Aluminum Pan Al + FeCl3  Fe + AlCl3

  26. potassium sodium calcium magnesium aluminum zinc chromium iron nickel tin lead Hydrogen copper silver platinum gold Activity series of metals Al + Fe+3 Fe + Al+3 Fe + H+ Fe+3 + H2 increasing reactivity Element give e’s to ion lower on list

  27. Double Replacement Reaction AX + BY  BX + AY BaCl2(aq) + Na2SO4(aq)  BaSO4(s) + 2NaCl(aq) Insoluble Precipitate Formed Ba+2Cl-1 Na+1 SO4-2

  28. Double Replacement Reaction AX + BYBX + AY • Predict the products: AgCl(s) + Mg(NO3)2(aq) 2 AgNO3(aq) + MgCl2(aq) 2 Write correct formulas then balance as needed Ag+NO3- Mg+2 Cl-

  29. Oxidation and reduction • REDOX • Where reactants exchange electrons - • Examples: • All types of batteries • alkaline, NiCad, car batteries • Rusting and corrosion • Metabolism • Antioxidants (Vit C, E prevent oxidation)

  30. Oxidation and reduction REDOX Where reactants exchange electrons - Oxidation = Losing electrons LEO: Lose Electrons Oxidation Reduction = Gaining electrons GER: Gain Electrons Reduction LEO the lion says GER

  31. Reaction Rates Fast: Oxidation: Paper burning Slow: Oxidation: Nails rusting Paper turning yellow

  32. Reaction Rates For reactants to make products: • They have to have enough E. • Molecules must collide • (solvents really help) • They have to be alignedcorrectly. (Parked cars don’t collide)

  33. 8 blocks: 34 surfaces 8 blocks: 24 surfaces Reaction Rates Factors that increase reaction rate: • More Reactants: More cars  More collisions More surface area  More collisions

  34. Reaction Rates Factors that increase reaction rate: • Higher Temperature: Faster cars  More collisions More Energy  More collisions

More Related