Rates of reaction and equilibrium
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Rates of Reaction and Equilibrium . Rates of reaction = kinetics Equilibrium = balance . To react, atoms must get together: . Called the collision theory: Students act a chemical reaction 1. 2. 3. . To react, atoms must: . 1. Get together (collide)

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Rates of Reaction and Equilibrium

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Rates of reaction and equilibrium

Rates of Reaction and Equilibrium

  • Rates of reaction = kinetics

  • Equilibrium = balance


To react atoms must get together

To react, atoms must get together:

  • Called the collision theory:

    • Students act a chemical reaction

  • 1.

  • 2.

  • 3.


To react atoms must

To react, atoms must:

1. Get together (collide)

2. Get together in the right way (orientation)

Collide with the “correct” side of a molecule

NO₂ + CO ↦ NO + CO₂

Carbon must hit the O side of NO₂ to get one of the O from the NO.

3. Get together with enough energy (force) so that the electrons can be shared/transferred

  • Activation energy (low or high)


Rate of chemical reaction

Rate of chemical reaction:

Reaction rate of a chemical reaction:

measured by change in concentration per unit time


Reaction rates kinetics

REACTION RATES: KINETICS

  • Rate that reactants turn into products

    • Measured by change in concentration (of reactants or products)

      5 FACTORS AFFECTING REACTION RATES

      3 factors relate to energy

      2 factors relate to the particles


Review collision theory

Review collision theory

  • Chemical reactions happen when atoms and compounds collide with each other

    • Collide with sufficient force to break bonds

    • Collide in the right position (orientation)


Factors affecting collision theory why

Factors affecting collision theory - Why?

Energy

Characteristics

Concentration

Surface area

  • Temperature

  • Agitation

  • Catalysts


Energy kinetics rate

Energy & kinetics (rate)

  • 1. temperature: increases temp INCREASES reaction rates

    Why? *particles move faster and collide with greater intensity

    2. agitation: increases reaction rate

    Why? *increases likelihood of particles being exposed to one another; increase in collisions

    examples: shaking, stirring


Energy kinetics

Energy & kinetics

3. catalysts: substance that increases the reaction rate without being used up in the reaction.

Why? * lowers the ACTIVATION energy;

sort of “invites” reacting particles together so they will react


Solutions kinetic

Solutions & kinetic

  • concentration: increasing concentration of reactants increases rate

    Why? *increasing # particles increases chance of collision resulting in a reaction


Rates of reaction and equilibrium

  • 2. surface area: increasing will cause reaction rate to increase

    Why? *greater exposure of reacting particles to each other

    examples: pulverizing, crushing, chopping up, etc

    Example: Logs vs. twigs


Collision theory

Collision Theory

  • Speed up the rate of reaction

  • https://www.youtube.com/watch?v=OttRV5ykP7A


Chemical equilibrium balance

Chemical Equilibrium = Balance


Chemical equilibrium key terms

Chemical EquilibriumKey Terms

  • Reversible reactions

  • Balance

  • Impacted by concentration, temperature and pressure

  • Closed system (no new reactants added, no product is removed)

  • Equilibrium constant

    • Keq = [products]

      [reactants]


Chemical reaction equilibrium

Chemical Reaction Equilibrium

  • Reversible reactions: ↔⇄

  • Explain what a reversible reaction will do to products and reactants


Chemical reaction equilibrium1

Chemical Reaction Equilibrium

  • Reversible reactions: ↔⇄

  • Often happens naturally

  • Products can be turned back to reactants

  • In other words:

    Products recombine to form the original substances .


Reversible reactions and equilibrium

Reversible reactions and Equilibrium

  • Equilibrium = balance between the amount of reactants and products in a reversible reaction

    Needs a closed system: no additional reactants added and no products are taken away or escape as a gas)

    Dynamic equilibrium Forward and backward reactions taking place at the same rate


Chemical equilibrium

Chemical Equilibrium


Chemical equilibrium balance1

Chemical Equilibrium = Balance


Rates of reaction and equilibrium

Achieving equilibrium: After a period of time, the concentrations of reactants and products will stabilize


Le chatelier principle

Le Chatelier Principle

  • If you change the conditions, the position of the equilibrium will shift to oppose the change.

  • Apply stress


Upsetting the equilibrium to make more product

Upsetting the equilibrium to make more product

Upsetting the equilibrium = shifting the equilibrium

  • Change temperature

    If an endothermic reaction -absorb or release heat?

    -example of types of reaction?

    CaCO₃ + heat ⇄ CaO + CO₂

    Add more heat (raise the temperature) to make more product

    If an exothermic reaction– reduce the amount heat (lower the temperature) to make more product

    Reaction will try to replace the heat that was taken away


Upsetting the equilibrium to make more product1

Upsetting the equilibrium to make more product

  • Change the pressure

    • Important when gases react

    • Many reactions will have greater volume on one side (more product or more reactant)

      If we increase the pressure –

      The reaction will “favor” the reaction side with less volume

      If we lower the pressure –

      The reaction will “favor” the reaction side with more volume

      N₂ + 3 H₂ ⇄ 2NH₃


Haber process

Haber Process

  • TED Ed Lessons

  • https://ed.ted.com/lessons/the-chemical-reaction-that-feeds-the-world-daniel-d-dulek

  • New concept: equilibrium


Le chatelier principle1

Le Chatelier Principle

  • If you change the conditions, the position of the equilibrium will shift to oppose the change.


Stresses disrupt the balance

Stresses disrupt the balance


Equilibrium constant

Equilibrium constant

  • aA + bB⇆ cC + dD

  • Keq= [C] [D]

    [A] [B]

  • Example: N₂ + 3 H₂ ⇄ 2NH₃

  • Keq = [NH₃]²

    [N₂] [H₂]³

  • Add coefficients at exponents

    Will use equilibrium constant when determining pH and pOH


    Issues chemical reactions good evil

    Issues- Chemical reactions Good & Evil

    • Haber received much criticism for his involvement in the development of chemical weapons in pre-World War II Germany, both from contemporaries and from modern-day scientists.

    • The research results show the ambivalence of his scientific activity: on the one hand, development of ammonia synthesis for the manufacture of explosives and of a technical process for the industrial manufacture and use of poison gas in warfare; but on the other hand, development of an industrial process without which the food supply for today's world population would be greatly diminished


    Review energy in chemical reactions

    Review: Energy in chemical reactions

    Exothermic chemical reaction


    Review energy in chemical reactions1

    Review: Energy in chemical reactions

    Endothermic chemical reaction


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