KA1- Controlling The Rate Flashcards
Equation used when difficult to measure change in chemical reaction
Rate = 1/time
Time= 1/rate
Successful collisions occur when
The collision geometry is correct
Particles have the e right amount of energy
Increasing concentration/ pressure
Increases rate of reaction because more particles in the same place- more move about- more likely to have collisions- if particles colliding have sufficient energy successful collision will occur
Decreasing particle size
Increase rate of reaction because more surfaces are exposed and it is only the particles on the surface of a solid that can react- more particles available to react
Increasing temp
Particles have more kinetic energy- collide with greater force
Temperature
Measure of the average kinetic energy of the particles in a substance
Activation energy
Can be shown on potential energy diagram
The minimum amount of kinetic energy colliding particles must have to react
If particles dont have enough energy to react
Energy must be supplied ( spark or lit match )
Collision theory
States reactants must collide with correct geometry
Collision geometry
Refers to the position of the reactants when they collide
Enthapy change (/\H)
The energy change that occurs when reactants are converted into products
Exothermic reactions
Products have less energy than the reactants, heat energy is released to surroundings, /\H as a negative value (shows energy lost o surroundings)
Endothermic reactions
Products have more energy than the reactants, energy taken in/gained from surroundings, shown with the positive /\H value
/\H
Hproducts
Hreactants
Activated complex
An unstable arrangement of atoms
Very high in energy
