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CHEMICAL REACTIONS - Coggle Diagram
CHEMICAL REACTIONS
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Reversible Reactions
The symbol of reversible reactions are: ⇌
The products can then react with each other or decompose to form the reactant molecules.
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Rates of Reaction
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Collision Theory : Successful collisions have enough activation energy to break pre-existing bonds and form new bonds at the moment of impact.
Concentration
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Higher-concentration reactants contain more particles per unit volume, increasing the successful collision and reaction rates.
When the concentration changes in the rate of reaction graph, the collision energy will remain the same, but the collision rate will increase (activation energy does not change).
Temperature
Increasing temperature increases the rate of reaction
Increased temperatures lead to increased average kinetic energy of particles. Particle movement produces energy greater than/equal to activation energy; an increased successful collision rate leads to an increased reaction rate.
Surface Area of Solids
Decreasing the particle size increases the rate of reaction
Decreasing particle size increases surface area; more reactant particles are exposed to collide, so the successful collision rate increases. This results in an increased rate of reaction
Pressure
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There are more particles per unit volume; the successful collision rate increases, resulting in an increased reaction rate.
Catalyst
A catalyst is a substance that increases the reaction rate by lowering the activation energy and is left unchanged at the end of the reaction.
More particles will have an energy greater than or equal to the activation energy, therefore successful collision rate increases resulting in an increased rate of reaction
For gaseous reactants, if the catalyst is solid metal, the catalyst provides a surface for the reaction.
The larger the surface area of the metal catalyst, the larger the area for the reaction to take place; therefore higher the rate of reaction
Enzymes are biological catalysts that speed up reactions but remain chemically unchanged.
Enzymes function best at optimum temperature and pH level; otherwise, they may denature and completely stop functioning.
Equilibrium
Le Châtelier’s Principle: if conditions of equilibrium are changed, the position of the equilibrium moves to oppose change
Temperature: Temperature lowered; equilibrium moves in exothermic direction. Temperature increases; equilibrium moves in the endothermic direction.
Pressure: Pressure raised; equilibrium moves to the side with the fewest gas molecules. Pressure lowered; equilibrium moves to the side with most gas molecules.
Concentration: Decreasing reactant concentration or increasing product concentration; equilibrium moves to the reactant side. Increasing reactant concentration or decreasing product concentration; equilibrium moves to the product side.
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