Reaction Rates

How does temperature effect reaction rate?

• Higher temperatures slow down reaction rate.
• Temperature has no impact on reaction rate.
• Increasing temperature

  1. Particles move slowly, Fewer collisions

     • Less likely to overcome activation energy → faster reaction rate

• 1. Increasing temperature gives particles more kinetic energy, so they move faster.

     • Faster-moving particles collide more often, which increases the chance of a reaction. =faster reaction rate

How does surface area effect reaction rate?

• Surface area decreases reaction rate by limiting collisions.
• Surface area has no effect on reaction rate whatsoever.
• Surface area only affects the temperature of the reaction.

  • A large solid piece has far more area exposed, so fewer collisions occur.

  • The reaction happens more quickly because fewer particles can react at the same time.

• When a solid reactant is broken into smaller pieces or powdered, more of its particles are exposed to other reactants. This increases the frequency of collisions, which speeds up the reaction.

  A large solid piece has less area exposed, so fewer collisions occur.

  • The reaction happens more slowly because fewer particles can react at the same time.

How does concentration impact reaction rate?

• Lower concentration decreases reaction rate due to fewer collisions.
• Concentration has no effect on reaction rate at all.
• Higher concentration slows down the reaction rate significantly.

  Lower concentration → high reaction

  • More particles in the same volume → more collisions

  • Reaction rate increases because fewer collisions have a chance to occur.

• Higher concentration increases reaction rate due to more frequent collisions.

  • When the concentration of a reactant is increased, there are more particles in the same volume.

  • This increases the frequency of collisions between reactant particles, which speeds up the reaction.

  • Lower concentration → slower reaction

    • Fewer particles in the same volume → fewer collisions

    • Reaction rate decreases because fewer collisions have a chance to occur.

How does Collision Theory accounts for the impact of temperature on reaction rate.

• Collision Theory states that lower temperatures decrease particle speed and reaction rates.
• Collision Theory indicates that temperature has no effect on the frequency of collisions.
• Collision Theory suggests that higher temperatures reduce the energy of particles, slowing reactions.
• Collision Theory explains that higher temperatures increase particle energy and collision frequency, thus increasing reaction rates.

In order for a reaction to occur there must be a

successful collision. What are the 3 requirements for a successful

collision in collision theory?

• (a) reactant particles must collide

  • (b) reactant particles must collide with sufficient energy (intensity) to

  break old bonds and form new ones

  • (c) low humidity

• •(a) excessive pressure

  • (b) reactant particles must collide with sufficient energy (intensity) to

  break old bonds and form new ones

  • (c) reactant particles must collide with the correct orientation (position

• (a) reactant particles must collide

  • (b) reactant particles must collide with sufficient energy (intensity) to

  break old bonds and form new ones

  • (c) reactant particles must collide with the correct orientation (position

• High temperature
• Random movement

What Factors Affect Reaction Rate?

• Pressure, humidity, volume, inhibitors, and temperature fluctuations.
• Color, shape, size, pressure, and light exposure.
• Time, distance, mass, energy, and temperature variations.
• Temperature, concentration, surface area and light sensitivity.

How does light intensity effect reaction rate?

• Higher light means, there is an increased energy which ramps us

  the frequency of successful collisions (more collisions per unit of

  time)

• Lower light intensity decreases the reaction rate of photosynthesis only.
• Light intensity has no effect on the rate of photosynthesis.
• Higher light intensity slows down the reaction rate of photosynthesis.