1 / 24

Understanding Chemical Reactions and Balancing Equations

This chapter provides an in-depth look at chemical reactions, emphasizing the importance of balancing chemical equations. It introduces key concepts such as reactants, products, catalysts, and the symbols used to represent various states of matter. The text explains the Law of Conservation of Mass and outlines rules for balancing equations. Types of reactions discussed include combination, decomposition, single and double replacement, and combustion reactions. Each section provides examples to illustrate the processes involved in balancing and understanding chemical equations.

keaton-davenport
Télécharger la présentation

Understanding Chemical Reactions and Balancing 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. Chapter 7 Balancing Chemical Equations

  2. Chemical Reaction • Describes chemical reaction. • Chemical equation: reactants yield products Catalyst = substance that speeds up a reaction without being used up.

  3. Symbols Used • (s) solid • (l) liquid • (g) gas • (aq) aqueous (in water solution) • gas as a product • ppt. (precipitate) • D means with heat • Pt means with Platinum catalyst

  4. Balancing Chemical Equations • Balanced equations have: the same # of atoms of each element on each side of the equation. • Law of Conservation of Mass – atoms can neither be created nor destroyed, simply rearranged.

  5. Rules for Balancing Equations • Get the correct formulas for reactants and products. • Write reactants on left, products on right and use plus signs and arrows when needed. • Count the # of atoms of each element in reactants and products.(Polyatomic ions on both sides count as one.) • Balance # of each element using coefficients. • Coefficient – whole # in front of a formula.

  6. Rules for Balancing Equations • Check each element to make sure equation is balanced. • Make sure all coefficients are in the lowest whole number ratio. Do not change subscripts!!!

  7. Diatomic Molecules Diatomic Molecules- a molecule made up two atoms of the same element. They are only diatomic when they are alone. • There are 7 naturally occurring • diatomic molecules. HONClBrIF

  8. 5 Types of Reactions - 1 Combination Reaction – elements combine to form a compound. A + B AB

  9. Examples of Combination Reactions 1. 2 Na + Cl2 2 NaCl 2 2. Cu + S Cu2S 3. SO3 + H2O H2SO4 4. CaO + H2O Ca(OH)2 2 MgO 5. Mg + O2 2

  10. 5 Types of Reactions - 2 Decomposition Reaction – elements break down into its element. AB A + B

  11. Examples of Decomposition Reactions 1. 2 NaCl 2 Na + Cl2 2 2 2. H2O H2 + O2 2 3. HgO 2 Hg +O2 Challenge: Copper I Chloride Decomposes 2CuCl 2Cu + Cl2

  12. 5 Types of Reactions - 3 Single Replacement Reaction – one element replaces another element in a compound. AB + C A + CB or AB + D AD + B + - + + + - + - - + - -

  13. Reactivity Series of Metals and Non-Metals • The single metallic element will only replace the metal in a compound if it is more reactive. • A chart is used to determine if the lone metal is more reactive. If not, no reaction occurs. • The single non-metallic element will only replace the non-metal in a compound if it is more reactive. The higher up in the group the non-metal is, the more reactive it is.

  14. Examples of Single Replacement Reactions 1. Zn + H2SO4 ZnSO4 + H2 2. K + HOH KOH + H2 2 2 NaCl + Br2 3. Cl2 + NaBr

  15. 5 Types of Reactions - 4 Double Replacement Reaction – two compounds react and exchange positive ions to form two new compounds. AB + CD AD + CB + - + - + - + -

  16. Examples of Double Replacement Reactions 1. NaOH + H2SO4 Na2SO4 + HOH 2 2 2. BaCl2 + K2CO3 BaCO3 + KCl 2 3. FeS + HCl 2 H2S + FeCl2

  17. 5 Types of Reactions - 5 Combustion Reaction – oxygen reacts with a compound composed of C and H. CxHy + O2 CO2 + H20 Also called Burning (exothermic) The products are always CO2 and H2O.

  18. Examples of Combustion Reactions 1. C6H6 + O2 CO2 + H2O 7½ 6 3 2 15 12 6 C6H6 + O2 CO2 + H2O 2. CH3OH + O2 CO2 + H2O 1½ 2 2 3 2 4 CH3OH + O2 CO2 + H2O

  19. Special Decomposition Reactions: 1 • Decomposition of a Carbonate: XCO3 XO + CO2 ex. Na2CO3 Na2O + CO2

  20. Special Decomposition Reactions: 2 • Decomposition of a Hydroxide: XOH XO + H2O ex. 2NaOH Na2O + H2O

  21. Special Decomposition Reactions: 3 • Decomposition of a Chlorate: XClO3 XCl + O2 ex. NaClO3 NaCl + O2

  22. Special Decomposition Reactions: 4 • Special single Replacement Reaction: • Group IA or IIA metal and H2O X + HOH XOH + H2 ex. 2Na + 2HOH 2NaOH + H2

  23. How to ID types of reactions. Combination Reactions – given 2 items that form 1 new compound. Decomposition Reactions – given a single compound that breaks into parts. Single Replacement – given a single elementplus a single compound, forms a new compound a a different element. Double Replacement – given two compounds (+’s or –’s change places). Combustion Reaction – given CH compound with Oxygen, always forms water and carbon dioxide.

  24. The End

More Related