Chapter 14 Notes.docx - Chapter 14 Notes Video 1 Catching...

This preview shows page 1 - 3 out of 10 pages.

Chapter 14 Notes Video 1 Catching lizards and ectotherms Lizards, and other cold blooded creatures, are ectotherms or animals whose body temp matches their environment’s temp When a lizard’s body temp drops, the chemical reactions that occur in its body slow down as do all chemical reactions when cooled This causes the lizard to become lethargic and to slow down Chemical kinetics is the study of the factors that affect the rates of chemical reactions, such as temp. Why do we need to study kinetics? Time taken by medicine to improve your symptoms Medical professionals, biologists Time taken to cook a meal – your mom Design an engine that lets efficient burning of gasoline – engineers Expiration dates on food products and rate of food spoilage – chemists, grocers Role of refrigerants such as CFC’s in the degradation of the ozone layer, geologists, environment What is chemical kinetics Kinetics is the study of how fast (rate) chemical reactions occur A reaction is slow or fast depending on the relative strength of the chemical bonds Chemical reactions involve a combination of bond breaking for reactants and bond making for new products Reactants need to come together and collide with one another to react In order to increase the speed of the reaction, increase the change of collisions between the reactants Factors that influence reaction rate Under a specific set of conditions, every reaction has its own characteristic rate, which depends upon the chemical nature of the reactants Five factors cab be controlled during the reaction: 1. Concentration: molecules must collide to react 2. Physical state: molecules must mix to collide 3. Temp: must collide with enough E to react 4. Surface area: more possible interactions 5. The use of a catalyst Factors affecting reaction rate: reactant concentration and temp The greater the concentration of reactant molecules, the faster the reaction This increases the frequency of reactant molecule contact Steel wool burns slower in air (21% O 2 ) then 100% O 2 atmosphere Increasing temp increases the reaction rate for most reactions For every 10 rise in temp, the speed of the reaction doubles
Milk spoils easily due to bacterial reactions at room temp compared to refrigerated conditions Factors affecting reaction rate: nature of the reactants, surface area and state Nature of the reactants refers to what kind of reactant molecules there are and what physical conditions they are in Small molecules tend to react faster than larger molecules Gases tend to react faster than liquids, which react faster than solids Powdered solids are more reactive than, “blocks” More surfaces area for contact with other reactants Reactants in the solid phase have a higher reaction rate when the surface area is maximized, more collisions are made possible For fast relief of an acid stomach, grind the antacid instead of

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture