Topic 7a- Rates of reaction (paper 2) Flashcards
what is the calculation for rate of reaction?
quantity of reactant used or product formed / time
in what ways can you measure the formation of a product for rates of reactions?
- precipitation (the cross under a beaker and a timer)
- change in mass (timer and balance)
- volume of gas given off (bung with syringe and timer)
what factors affect the rate of reaction?
- temperature
- concentration
- surface area
what two things does collision theory say that the rate of reaction depends on
- collision frequency of active particles
- energy transferred during collision (particles have to collide with enough energy to be successful)
how does temperature cause an increased rate of reaction?
- Increased temperature results in particles moving quicker
- Therefore there are more frequent successful collisions between particles
how does increased concentration or pressure cause an increased rate of reaction?
particles are closer together causing more frequent successful collisions
what is the link between the rate of a reaction and the frequency of successful collisions
the rate of reaction is directly proportional to the frequency of succesful collisions within a reaction
what is a catalyst
A catalyst is a subastance which can speed up a reaction, without being chemically changed or used up in the reaction and without changing the reaction products.
what are enzymes?
biological catalysts
how do catalysts work in a reaction
catalysts work by offering an alternative reaction pathway that requires a lower activation energy
what part of an energy-time graph shows the activation energy?
the change in height between the top of the curve and the initial energy of the reactants
what can enzymes be used for
the production of alcoholic drinks
