energy diagrams: drawing it out. why are we learning this? energy diagrams show how a reaction...
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Energy Diagrams: Drawing it Out
Why are we learning this?
Energy diagrams show how a reaction works.
Energy diagrams display The energy of reactants and products The energy needed for a reaction to occur The energy absorbed or released due to
reaction
Energy Diagram Parts Potential Energy of the reactants Potential Energy of the products Activation Energy E – the amount of energy
required to reach the transition state or activated complex from the reactant
Transition State, Ts (Activated Complex) – when bonds break and form and reactants become products
Enthalpy, H – science word for heat, Energy of products – energy of reactants
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products
Potential Energy
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products
Potential Energy
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products max
Potential Energy high low
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products max
Potential Energy high low Kinetic Energy
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products max
Potential Energy high low Kinetic Energy
high min low
Potential and Kinetic Energy Changes during a CollisionEndothermic Reactants Activated Complex Products max
Potential Energy high low Uphill- endothermic! Kinetic Energy
high min low
Putting Pieces TogetherTransition State, Ts
Energy
Reaction
Reactants
Products
Activation Energy of forward reaction, EF
EF = Ts - ReactantsEnthalpy of forward reaction, HF
HF = Products - Reactants
Putting Pieces TogetherTransition State, Ts
Energy
Reaction
Reactants
Products
Activation Energy of reverse reaction, ER
ER = Ts - ProductsEnthalpy of forward reaction, HR
HR = Reactants - Products
Types of Energy Diagrams Endothermic – the reaction absorbs heat so
H is positive The reactants have less potential
energy than the products
A + B
AB
H > 0
A - - - B
Types of Energy Diagrams Exothermic – the reaction releases heat so
H is negative The reactants have more potential
energy than the products
A + B
ABH < 0
A - - - B
Types of Energy Diagrams Catalysts lower the activation energy of a
reaction by finding an alternate route. However, the change in heat, or enthalpy is the same.
A + B
ABH < 0
Blue without Catalyst
Green with Catalyst
A - - - B
Try it together
50
100
150
200
250
Use the numbers to find:
What is EF?
What is HF?
What is HR?
What is ER?
Pick the slow and fast reaction
Ea Ea
Slow Fast- low Ea
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