Collision Theory
What are the two main conditions for a successful collision?
Correct orientation and sufficient energy (activation energy).
How does increasing surface area affect reaction rate?
More surface area means more particles are exposed for collisions, increasing reaction speed.
Why does sugar dissolve faster in hot water?
Higher temperature increases particle movement, leading to more frequent and energetic collisions.
Balance this equation: H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
True or False: A catalyst is used up in a reaction.
False – A catalyst speeds up a reaction without being consumed.
What is activation energy?
The minimum amount of energy required for reactants to form products.
Why does higher concentration speed up a reaction?
More reactant particles in a given volume increase the frequency of collisions.
How does grinding a solid reactant into powder affect its reaction rate?
It increases surface area, allowing more collisions and a faster reaction.
Balance this equation: Na + Cl₂ → NaCl
2Na + Cl₂ → 2NaCl
True or False: A lower concentration of reactants leads to a higher reaction rate.
A lower concentration means fewer collisions, slowing the reaction.
According to Collision Theory, why don’t all collisions result in a reaction?
Some collisions don’t have enough energy or the correct orientation.
What role does a catalyst play in a reaction?
It speeds up the reaction by lowering activation energy without being consumed.
Why do effervescent tablets fizz faster in warm water?
Increased temperature increases reaction rate by providing more energy for collisions.
Balance this equation: C + O₂ → CO
2C + O₂ → 2CO
True or False: Increasing temperature always increases the reaction rate.
True – Higher temperature means more frequent and energetic collisions.
How does increasing temperature affect collisions?
Particles move faster, collide more frequently, and with more energy, increasing the reaction rate.
How does decreasing temperature affect reaction rate?
It reduces the kinetic energy of particles, leading to fewer and weaker collisions, slowing the reaction.
How does a catalytic converter in cars reduce pollution?
It uses catalysts (like platinum) to speed up harmful gas reactions, turning them into less harmful substances.
Balance this equation: C₃H₈ + O₂ → CO₂ + H₂O
C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
True or False: Increasing the surface area of a solid reactant speeds up a reaction.
True – More exposed particles lead to more collisions.
Why do catalysts lower activation energy?
They provide an alternative pathway with a lower energy requirement, increasing successful collisions.
Why does pressure affect the rate of gas reactions?
Increasing pressure forces gas particles closer together, increasing collision frequency.
Why do potatoes cook faster when cut into smaller pieces?
Smaller pieces have a larger surface area, allowing heat to penetrate more quickly, speeding up the cooking process.
Balance this equation: Zn + HCl → ZnCl₂ + H₂
Zn + 2HCl → ZnCl₂ + H₂
True or False: The rate of a reaction is only determined by temperature.
False – Other factors like concentration, surface area, and catalysts also play a role.