x Flashcards
what is meant by rate of reaction?
change in concentration of a reactant or a product in a given time
write an equation for the rate of reaction
rate= change in concentration/ time
what as the units for the rate of reaction?
moldm⁻³s⁻¹
state 5 factors that can affect the rate of reaction.
- concentration
- pressure
- catalyst
- temperature
- surface area
why are some collisions effective?
- correct orientation
- sufficient energy to overcome activation energy
how does increasing the concentration affect the rate of reaction?
- increases the number of particles in the same volume
- collide more frequently and closer together
- increases the rate of reaction
how does increasing the pressure of a gas affect the rate of reaction?
- the same number of particles but in a smaller volume
- closer together and collide more frequently
- increases the rate of reaction
2 methods of measuring progress of a chemical reaction
- monitoring the removal (decrease in concentration) of a reactant
- following the formation (increase in concentration) of a product
state 2 possible methods for monitoring the rate of reactions that produce gases
- monitoring the volume of gas produced at regular time intervals using gas collection
- monitoring the loss of reactants using a balance
what is a catalyst?
alters the rate of reaction without being used up
what effect does a catalyst have on the rate of a reaction?
- speeds up a reaction
- provides an alternative route
- catalyst is regenerated
- catalyst may react with a reactant to form an intermediate
complete an enthalpy profile diagram of an exothermic reaction, with and without a catalyst
see page 149
complete an enthalpy profile diagram of an endothermic reaction, with and without a catalyst
see page 149
what is a homogenous catalyst?
same physical state as the reactants
give 2 examples of homogenous catalysts with equations
- making esters with H₂SO₄
C₂H₅OH(l) + CH₃COOH(l)→ CH₃COOC₂H₅(l) + H₂O (l) - ozone depletion with Cl• (g)
2O₃ (g) → 3O₂ (g)