Managing Chemical Processes 1.0 Flashcards
(31 cards)
The rate of Reaction is expressed as:
- the rate of formation of a product.
- the rate of consumption of a product.
The average rate of reaction
- rate over a period of time.
- change in reactant or product over a period of time
Instantaneous rate of change
- the rate at a particular instant of time.
- the slope of the tangent at a specific time is the IRC
For collisions to be productive, the reactants must:
- have the minimum kinetic energy necessary for breaking bonds and forming new ones. (Ea)
- corrected orientation
Reaction Rate depends on:
- the magnitude of Ea barrier
- frequency of collisions
- the energy of collisions relative to Ea
- orientation
Factors that affect RxR
- Concentration of Reactants
- Pressure
- Temperature
- Surface area of solid reactants
- Catalysts
It cannot be ensured that every collision is orientated in a productive manner but…
conditions can be manipulated to enhance the probability of a successful occurring. Thus, increasing the rxr per unit time.
For a reaction to successfully occur (in terms of activation energy):
must possess the energy that is equal to or greater than the activation energy.
The concentration of reactants increase
Rate of reaction increases
Structured Response: Why does an increase in concentration allow for an increase in rxr?
If the concentration of reactants is increased, the rate of reaction is also increased. More particles are present within a defined volume, increasing the probability of a successful collision per unit time.
Increase in Concentration
If collisions are spontaneous in reaction vessels and there are more particles within a volume the higher the probability for a successful collision.
As the pressure of a reaction vessel is increased…
The rxr will increase.
Pressure Increase
Affects gasses only
Volume decrease = pressure increase
= concentrates the particles in a reaction vessel, increasing the rxr per unit time
Concentration Structured Response
If the concentration of reactants is decreased, the rate of reaction is also decreased. Fewer particles are present within a defined volume, decreasing the probability of a successful collision per unit time.
As the temperature of the reaction mixture increase
The rate of rxr increases.
Increasing Temp
Provides reactants with more kinetic energy, thus more collisions have sufficient energy to overcome the activation barrier.
- particles have high energy, more frequent and successful collisions
- does not change the magnitude of the Ea.
As the surface area of solid reactants increases
The rxr will increase.
Catalysts will increase…
the rate of reaction.
Catalysts
Lowers magnitude of Ea - provides an alternate pathway that is lower in Ea.
- Correctly orientates reactants - positions
Photosynthesis Equation:
6CO2 + 6H20 ——-> C6H1206 + 602
The intensity of Incident Light
Increasing IIL = increases the rate of photochemical reactions.
Energy Profile Diagram
describe the change in energy of a system.
Energy Profile Diagram: Exothermic
Higher vertical start of reactants
Energy Profile Diagram: Endothermic
Lower vertical start of reactants
