Reactivity 2.2 Flashcards
Change in concentration - change in volume
When a gas is evolved
Rate of chemical reaction
Increase in concentration of one of the products per unit time (mol dm-3 s-1)
Change in concentration - change in mass
When a gas is evolved
Change in concentration - change in acidity
Measure pH
Change in concentration - change in colour
Measure absorption
Change in concentration - change in ionic concentration
Measure electrical conductivity
Rate of reaction at any stated time
Is equal to the gradient of the graph at the time
Collision theory
For a reaction to occur between two particles, the two species must collide with correct orientation and sufficient energy.
Activation energy
Minimum energy required for a collision to occur
Maxwell-Boltzmann energy distribution curve
Particles in gas have a range of Ek and can be expressed in this curve
What are the four factors that affect the rate of reaction?
- Concentration
- Temperature
- Surface area
- Catalyst
How does increasing concentration increase rate of reaction?
More collision occur per second (although percentage of successful collisions remains the same)
How does increasing temperature increase rate of reaction?
More collisions per second as the particles are moving faster and more reacting particles have minimum energy to react
How does increasing the surface area increase rate of reaction?
Particles on the surface come into contact with surrounding reactants
How does a catalyst increase rate of reaction?
Catalysts increase the rate of reaction by bringing reactive parts of the reactants into close contact with each other, providing an alternate pathway for the reaction with lower Ea.
