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Learn about kinetics, the branch of chemistry that measures the speed or rate of chemical reactions. Explore topics such as potential energy diagrams, activated complex, collision theory, factors influencing reaction rate, and the role of catalysts.
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Flashcards for Unit 13 Kinetics
Kinetics Branch of chemistry measuring the speed or rate of chemical reactions
Potential Energy diagrams for reactions Hill diagrams! Don’t just show the net change. They show how the enthalpy changes over the entire reaction.
Endo: starts low, ends high Endo or Exo?
Exo: starts high, ends low Endo or Exo?
Activated Complex Reactants Products Identify reactants, products, activated complex
Potential energy of reactants Identify the arrow
Activation energy of forward rxn Identify the arrow
Heat of reaction Identify the arrow
Activation energy of reverse reaction Identify the arrow
Potential energy of activated complex Identify the arrow
Potential energy of products Identify the arrow
Collision Theory Effective collisions between reacting particles must occur for a reaction to take place.
Effective Collisions Energetic Favorable Orientation
Rate of reaction The speed of the reaction. The faster it occurs, the greater the rate.
6 Factors that influence the rate of reaction Nature of reactants (ionic or covalent) Temperature Concentration Pressure (for gases) Surface area (for heterogeneous reactions) Presence of a catalyst
Raising the temperature increases the reaction rate by Increasing both the number of collisions and the efficiency of the collisions.
As the concentrations of the reactants , the rate of rxn … increases
As the pressure of a gas-phase reactant , the rate of rxn … Increases.
More surface area Which 4.0-gram Zn sample will react faster with acid, and why? Lump Bar Powdered Sheet metal
How does a catalyst work? Provides an alternate reaction pathway with a lower activation energy.
Which reacts faster: ions in solution or covalent molecules? Ions in solution.
Which reacts faster in water: 1 cm3 of Na or 1 cm3 of Ca? 1 cm3 of Na - Nature of the metals
Which is usually slower, an organic reaction or an inorganic reaction? Organic, because organic particles contain covalent bonds.
Lowers the activation energy. Effect of a catalyst?
Potential energy of reactants Identify the arrow
Activation energy of forward rxn Identify the arrow
Activation energy of reverse rxn Identify the arrow
Potential energy of activated complex Identify the arrow
Heat of reaction Identify the arrow
Potential energy of products Identify the arrow