factors affecting chemical reaction

1. Factors Affecting
Rates of
Chemical
Reaction

2. • To a scientist, a reaction rate
means how quickly or slowly a
reaction takes place.
• Scientific studies have shown
that there are five factors that
affect reaction rates.
• They are temperature,
concentration, surface area,
the presence of a catalyst and
the nature of the reactants.
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3. Temperature
• Temperature is the measure of the
kinetic energy, or energy of motion,
in the particles of a substance.
• As temperature increases, the
particles move faster and come in
contact more often.
• In order for two substances to react,
the particles of those substances
must collide with each other.
• For example: Foods cook slowly at
low temperatures than at high
temperatures.
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5. Surface Area
• For a reaction to occur, substances must
come in contact with each other.
• Contact can only take place at the surfaces
of the substances involved in the reaction.
• As the surface area increases, the rate of a
reaction increases because more particles
can come together.
• The surface area of reactants affects the
rate of reaction. If the size of a particle is
small, the surface area will be more and
this increases the speed of heterogeneous
chemical reactions.
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7. Concentration
• Concentration tells us how much solute
there is in a solution. As the
concentration of the chemical
increases, the chance of contact among
particles also increases.
• This causes an increase in the rate of
reaction.
• According to collision theory, the
greater the number of molecules the
higher is the collision ratio, thus the
rate of reaction is faster.
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9. Catalysts
• A catalyst is a substance that changes
the rate of a chemical reaction by
providing an alternate pathway,
lowering the activation energy.
• Most catalysts speed up reactions but
they are not changed or used up in a
reaction.
• They are the same at the beginning and
end of the reaction.
• Enzymes are considered as catalysts to
speed up the biochemical reactions in
the body.
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10. Application of the Factors Affecting
Rate of Reaction
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11. 1. Food and Pharmaceutical
products preservation
• Temperature is a very
essential factor in preserving
foods and medicines.
• High temperatures cause
higher collision and reactions
produce by microorganisms
that are why most of food
medicinal products are
stored in low temperatures.
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12. 2. Preservation or
decomposition of specimens
• Biochemical laboratories make use of liquid
nitrogen as cryogenic freezer in preserving
laboratory sample and specimens.
• This process is called cryopreservation
where cells or whole tissues are preserved
by cooling to low sub-zero temperatures.
• At low temperatures, any biological
activity, including the biochemical
reactions that would lead to cell death, is
effectively stopped.
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13. 3. Medication or poison
affecting the body
• It is essential to know the right
concentration of the drugs that we
take.
• Some drugs are more effective if taken
in higher concentrations. There are also
drugs that may poison our bodies if we
take an amount more than the
prescribed concentration.
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14. 4. Dating, restoration,
preservation of artifacts
• To preserve wood and leather
artifacts, these must be soaked in
polyethylene glycol.
• Polyethylene glycol is a waxy
substance that is absorbed into
wood and leather and makes
wood stronger and makes leather
flexible again.
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