1 / 34

Types of Chemical Reactions

Types of Chemical Reactions. First a few concepts to take into consideration…. In Unit 4 we learned how bonds are formed from elements, called compounds. In Unit 5 we will learn how those compounds form together through a process called a chemical reaction. What is a Chemical Reaction?.

barbra
Download Presentation

Types of 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. Types of Chemical Reactions

  2. First a few concepts to take into consideration… In Unit 4 we learned how bonds are formed from elements, called compounds. In Unit 5 we will learn how those compounds form together through a process called a chemical reaction

  3. What is a Chemical Reaction? • a process in which one or more substances change to make one or more new substances. • Baking bread, a space shuttle launch, & eating lunch are all examples of this

  4. What Are Some Signs of Chemical Reactions? Cu(s) + 4HNO3(aq)  Cu(NO3)2(aq) + 2NO2(g) + 2H2O

  5. What Are Some Signs of Chemical Reactions? 2 AgNO3(aq) + K2CrO4(aq) Ag2CrO4(s) + 2 KNO3(aq)

  6. What Are Some Signs of Chemical Reactions?

  7. What Are Some Signs of Chemical Reactions?

  8. How do you know a “Chemical” Reaction has taken place? • The MOST important sign • The formation of a new substance with different properties • Sugar reacting with sulfuric acid • The product is neither sugar nor acid

  9. Issues To Consider • Formulas show chemistry at a standstill • Equations show chemistry in action • Every chemical compound has a formula which cannot be altered • A reaction must account for EVERY atom used • The Law of Conservation of Matter

  10. Types of Chemical Reactions you NEED to know!-4 Types-

  11. Reaction #1 - Synthesis • Two or more elements combine to form a single, more complex compound • The Basic Form: A + BAB • The following are examples of synthesis reactions

  12. Synthesis Reactions • 2Mg + O2 → 2MgO • C + O2 → CO2 • 2Na + Cl2 → 2NaCl • MgO + H2O → Mg(OH)2

  13. Reaction #2 - Decomposition • A single compound breaks down into its component parts • The Basic Form: ABA + B • The following are examples of decomposition reactions

  14. Decomposition Reactions • CaCO3 → CaO + CO2 • 2KClO3 → 2KCl + 3O2 • H2SO4 → H2O + SO3 • 2NaCl → 2Na + Cl2

  15. Reaction #3 - Single Replacement/Displacement • A more active element takes the place of another element in a compound & sets the less active one free. • The Basic Form: A + BC AC + B • The following are examples of single replacement/displacement reactions

  16. Single Replacement/displacement Reactions • Fe + CuSO4 → FeSO4 + Cu • 2Mg + 2H2O → 2MgO+ 2H2 • 2Na + 2H2O → 2NaOH+ H2 • Cl2 + 2NaBr → 2NaCl+ Br2

  17. Reaction #4 - Double Replacement/Displacement • Also called an Ionic Reaction • A reaction will occur when a pair of ions come together and change places. • Sometimes called an Ionic Reaction • The Basic Form: AB + CD AD + CB • The following are examples of single replacement/displacement reactions

  18. Double Replacement/displacement Reactions • BaCl2 + Na2SO4 → 2NaCl+ BaSO4 • 2HCl + FeS → FeCl2 + H2S • NaCl + AgNO3 → NaNO3 + AgCl • HCl + NaOH → NaCl+ H2O

  19. Sec. 4: Energy and Rates of Chemical Reactions • Chemical Reactions have energy going in one of two directions • Going outward – Exothermic • Using energy • Releasing energy • The amount of energy when finished is less than when you started.

  20. Exothermic Reactions

  21. More Exothermic Reactions… • Energy released in an exothermic reaction is often written as a product in the balanced chemical equation. • 2Na + Cl2 2NaCl + energy • This reaction continues to emphasize the Law of Conservation of Matter/Mass.

  22. Exothermic Reaction Diagram Draw This!

  23. Energy and Rates of Chemical Reactions • Chemical Reactions have energy going in one of two directions • Going inward - Endothermic • Energy taken in • Storing energy • The amount of energy when finished is more than when you started.

  24. An Endothermic Reaction Photosynthesis is a great example of storing energy!

  25. More Endothermic Reactions… • Energy that is taken in during an endothermic reaction is often written as a reactant in a chemical reaction. • Photosynthesis • 6CO2 + 6H2O + energy C6H12O6 + 6O2 • This reaction continues to emphasize the Law of Conservation of Matter/Mass.

  26. Endothermic Reaction Diagram Draw This!

  27. What is the Law of Conservation of Energy? • Energy cannot be created or destroyed. • However it can change forms. • Energy can be transferred • Conduction, Convection, & Radiation • The total energy before a reaction will be the same as the total energy after the reaction.

  28. What is the “Rate” of a Chemical Reaction? • A chemical reaction takes place when particles collide with enough force to break bonds. • The speed at which new particles form is called the “rate of a reaction”

  29. What is Activation Energy? • The smallest amount of energy molecules need to react. • For example: • Matches have two chemicals on them that will ignite to create a flame (exothermic reaction) • However, those chemicals require energy to activate them - striking the match with friction.

  30. Sources of Activation Energy? • Friction • Electricity - spark • Light • Motion • Anything that transfers energy

  31. What Factors Affect the Rate of Reactions? • Temperature • High temperatures = increased rate of reaction • Concentration • High concentration = increased rate of reaction • Surface Area • Greater surface area = increased rate of reaction • Inhibitors • A substance that slows down the rate of reaction • Catalysts • A substance that speeds up the rate of reaction

  32. What is an Inhibitor? • A substance that decreases the rate of a reaction • Examples include: • Food preservatives • Some antibiotics • Cement setting inhibitors to prevent cement from drying too quickly

  33. What is a Catalyst? • A substance that increases the rate of reaction with LESS energy. • Examples include: • Catalytic converter on cars • Some glues use a catalyst to harden the glue

More Related