Collision Theory
This must happen between particles for a chemical reaction to occur.
What is a collision?
Raising this causes molecules to move faster and usually increases reaction rate
What is temperature?
The minimum energy required for reactants to form products is called this.
What is activation energy?
This fuel type vaporizes and mixes with air, igniting quickly with a spark — common in cars.
What is gasoline?
The experimental measure that records the time for half the reactants to be consumed
What is half‑life?
Even when particles collide, a reaction may not occur unless this condition about energy is met
What is having sufficient energy to overcome the activation energy?
Increasing this (particles per volume) raises collision frequency and often speeds reactions.
What is concentration (or pressure for gases)?
On a potential energy diagram this feature represents the activation energy.
What is the peak or 'hill' between reactants and products?
This fuel ignites under compression and tends to burn more gradually, useful for heavy trucks
What is diesel?
When testing surface‑area effects, this key variable must be kept constant between samples to avoid confounding
What is the total mass (amount) of reactant?
This temporary structure forms briefly when reactants collide and bonds are rearranging
What is the activated complex (or transition state)
This physical change (e.g., crushing a solid) increases exposed particle area and speeds reactions
What is increasing surface area?
Breaking bonds requires this kind of energy change (absorbed or released?)
What is energy absorbed?
This fuel has very fast flame speed and high performance but poses control and safety challenges
What is hydrogen?
If Trial X has half‑life 80 s and Trial Y has half‑life 20 s, this calculation shows how many times faster Y is than X
What is 80 ÷ 20 = 4 times faster?
Two things collisions must have for a reaction: sufficient energy and this.
What is the correct orientation?
This type of substance provides an alternate, lower‑energy pathway for reactions without being consumed.
What is a catalyst?
Making bonds generally results in this energy change
What is energy released?
Engineers control these three things (name any two) to manage combustion rate for safety and efficiency.
What is airflow and temperature? (Also: fuel particle size, catalysts, mixing strategies)"
In the Gizmo animation, increasing temperature produced these two observable changes in collisions (name both).
What are more frequent collisions and a greater fraction of collisions with enough energy to overcome Ea?
The theory that links collision frequency and energy distribution to reaction rate is named after this concept
What is collision theory?
This substance binds to a catalyst or active site and slows the reaction rate
What is an inhibitor
If a catalyst is added, this specific part of the potential energy diagram becomes smaller
What is the activation energy (Ea)?
Fast, high‑temperature combustion often increases formation of this pollutant produced from atmospheric nitrogen
What are nitrogen oxides (NOx)?
A student reports mean half‑lives at concentrations 0.4→120 s, 0.8→80 s, 1.2→60 s, 1.6→48 s, 2.0→36 s. This relationship suggests the half‑life is approximately proportional to this mathematical relationship with concentration.
What is an inverse (roughly 1/conc) relationship?