1 / 31

Chemical Reactions:

Chemical Reactions:. Reactants change chemical and physical properties. …. to become new substances made from the same elements; these are called products. When you write a chemical reaction…. The word equation explains what you begin with, and what you have at the end of the reaction.

chelsi
Télécharger la présentation

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. Chemical Reactions: Reactants change chemical and physical properties …. to become new substances made from the same elements; these are called products.

  2. When you write a chemical reaction… • The word equation explains what you begin with, and what you have at the end of the reaction. • The reactants FORM, YIELD, or MAKE the products. • Physical states may be included: • (aq) = aqueous • (l) = liquid • (s) or (cr) = solid or crystalline • (g) = gaseous Example: solid sodium reacts with water to form aqueous sodium hydroxide and hydrogen gas.

  3. Types of Reactions • Synthesis or Composition • Decomposition • Single Replacement • Double Displacement • Combustion Reactions A + B  AB HONCl BrIF A new twist To writing Formulas. These are Always written As diatomic Molecules. AB  A + B AB + C  AC + B AB + CD  AD + CB CxHy + O2 CO2 + H2O

  4. Writing Equations: • Subscripts describe the chemical composition of the substance. These are determined by the electrons in the atoms and MAY NOT BE CHANGED when balancing equations. • Coefficients are used to balance equations. 2 2 Na + Cl2 NaCl

  5. Composition/ Synthesis Reactions • A + X  AX • An element may react with oxygen to form the oxide (oxidation) X A

  6. Composition/ Synthesis Reactions • O2 + 2Mg  2 MgO • oxygen reacts with magnesium to form magnesium oxide Mg O O Mg

  7. Composition/ Synthesis Reactions • C + O2 CO2 • carbon reacts with oxygen to form carbon dioxide O C O

  8. Practice predicting reactions with oxide and sulfides O2 • 2Fe + ____  2FeO • 4 Fe + 3 ___  2 Fe2O3 • S8 + 8 O2  8 ____ • 8 Ba + S8  8 ____ O2 SO2 BaS

  9. More Composition/ Synthesis Reactions • Fe + S  FeS • Iron reacts with sulfur to form iron (II) sulfide S2- S Fe Fe2+

  10. More Composition/ Synthesis Reactions Na • Na + S  Na2S • Sodium reacts with sulfur to form sodium sulfide S2- Na+ S Na Na+

  11. Metals react with halogens. • 2Na + Cl2 2 NaCl • 2 Co + 3 F2  2 CoF3 • 2 K + I2  2 KI • Sr + Br2  SrBr2 • 2Mg + O2 2 MgO

  12. Synthesis reactions can also occur with oxides. • Active metal oxides react with water to form hydroxides. ex: • CaO + H2O  Ca(OH)2 • Many oxides of nonmetals react with water to form oxyacids. ex: • SO2 + H2O  H2SO3 • Some metal oxides react with nonmetal oxides to form salts. • CaO + SO2  CaSO3

  13. Practice • Active metal oxides react with water to form hydroxides. ex: • MgO + H2O  ________ • Many oxides of nonmetals react with water to form oxyacids. ex: • SO3 + H2O  _________ • Some metal oxides react with nonmetal oxides to form salts. • Na2 O + 2NO2  ________ Mg(OH)2 H2SO4 2 NaNO3

  14. DecompositionAX  A + X • 2H2O  2H2 + O2 H O H H O H Electrolysis: decomposition of a substance by an electric current.

  15. DecompositionAX  A + X • 2HgO  2Hg + O2 Hg O This reaction occurs when you heat orange colored mercury (II) oxide. Silver mercury and oxygen gas form. Hg O

  16. Decompositionof metal carbonatesACO3 AO + CO2(g) • CaCO3 (s) CaO (s) + CO2(g) O Ca This reaction occurs when you heat calcium carbonate. calcium oxide and carbon dioxide form. C O O

  17. Decompositionof metal hydroxidesAOH  AO + CO2(g) • Ca(OH)2 (s) CaO (s) + H2O (g) H O Ca This reaction occurs when you heat calcium hydroxide calcium oxide and water form. O H

  18. Decomposition of metal chloratesAClO3 ACl + O2(g) • 2KClO3 (s) 2KCl (s) + 3O2(g) O O Cl Cl K K O O This reaction occurs when you heat potassium chlorate. potassium chloride and oxygen form. O O

  19. Decomposition of acidsH2CO3 (aq) H2O (g) + CO2(g) O H H C Carbonic acid decomposes when warmed. water and carbon dioxide form. O O

  20. O O O O O O N N N N N N O O O O O O O O O O O O Single DisplacementA+ BX AX + Bor:Y + BX  BY + X • Replacement of a metal in a compound by another metal. 2 Al (s) + 3Pb(NO3)2 3Pb +2 Al(NO3)3 Pb2+ Al Pb2+ Al Pb2+

  21. O O O O O O N N N N N N O O O O O O O O O O O O Single DisplacementA+ BX AX + Bor:Y + BX  BY + X • Replacement of a metal in a compound by another metal. 2 Al (s) + 3Pb(NO3)2 3Pb +2 Al(NO3)3 Pb Al3+ Al3+ Pb Pb

  22. Single DisplacementA+ BX AX + Bor:Y + BX  BY + X • Replacement of a hydrogen in a compound by a metal. 2 Na (s) + 2 H2O (l) 2 NaOH (aq) + H2(g) H O Na Na H H O H

  23. Single DisplacementA+ BX AX + Bor:Y + BX  BY + X • Replacement of a hydrogen in a compound by a metal. Mg (s) + 2 HCl (aq) MgCl2(aq) + H2(g) Cl Mg H Cl H

  24. Single DisplacementA+ BX AX + Bor:Y + BX  BY + X • Replacement of halogens Cl2(g) + 2 KBr (aq) 2 KCl (aq) + Br2(g) Br Cl K Cl Br K

  25. O O N N O O O O Double Replacement Reactions (double displacement) • Formation of a precipitate. • 2 KI (aq) + Pb(NO3)2 (aq)  PbI2 (s) + 2 KNO3 (aq) I Pb2+ I K K

  26. Double Replacement Reactions (double displacement) • Formation of a gas. • FeS (s) + 2 HCl(aq)  H2S (g) + FeCl2 (aq) S Fe2+ Cl Cl H H

  27. Double Replacement Reactions (double displacement) • Formation of a water. • NaOH (s) + HCl(aq)  H2O (l) + NaCl2 (aq) H O Na+ Cl H

  28. Combustion Reactions • A substance combines with oxygen, releasing a large amount of energy in the form of light and heat. 2 H2 (g) + O2 (g)  2 H2O O H O H H H

  29. Combustion Reactions • A substance combines with oxygen, releasing a large amount of energy in the form of light and heat. C3H8 (g) +5 O2 (g)  4 H2O + 3 CO2 O O O O H O H H H C O C C O H O H H O H O

  30. Combustion Reactions • A substance combines with oxygen, releasing a large amount of energy in the form of light and heat. C3H8 (g) +5 O2 (g)  4 H2O + 3 CO2 O O H C O O H H H O H H O C H O O C O O H

More Related