1How can the rate of a chemical reaction be found?
found by measuring the quantity of a reactant used or the quantity of product formed over time
2State the formula for the mean rate of reaction?
quantity of reactant used / time quantity of product formed / time
3State the units that may be associated with these equations
g/s (grams per seconds) cm3/s (centimetre cubed per second) mols/s (moles per second)
4State which factors affect the rates of chemical reactions? (5)
-the concentrations of reactants in solution -the pressure of reacting gases -the surface area of solid reactants -the temperature -and the presence of catalysts.
5What does collision theory explain?
explains how various factors affect rates of reactions
6Define collision theory
Chemical reactions can occur only when reacting particles collide with each other and with sufficient energy.
7Define Activation Energy
The minimum amount of energy that particles must have to react is called the activation energy.
8What is the rate of a chemical reaction determined by?
The frequency of succesful collisions, hence, The no. of succesful collisions per second determines the rate of reaction
9Describe the relationship between conc. and rate of reaction
greater. conc. in same volume → more succesful collisions due to greater no. of particles → increased frequency → increased rate of reaction → proportional
10Describe the relationship between the SA of solid reactants and the rate of reaction
particlesases/liquids only react with the SA/outer layer of solid reactants greater SA → higher chance of. succesful collisions → increased frequency → rate of. reaction → proportional
11Describe the relationship between the temperature and the rate of reaction
greater temp. → more kinetic/internal energy for particles → more movement → greater frequency of succesful collisions → increased rate of. reaction → proportional
12What are Catalysts
Catalysts change the rate of chemical reactions but are not used up during the reaction.
13Define an activation energy barrier
The minimum amount of energy needed to be crossed by particles in order to react
14How do catalysts increase the rate of reaction?
Catalysts increase the rate of reaction by providing a different pathway for the reaction that has a lower activation energy.
15Explain catalytic action in terms of activation energy. (Expand on previous. answer)
by offering a different pathway, the activation energy. barrier is lowered, this means that particles can more succesfully collide to surpass the barrier and hence, increase the rate of. reaction
16Are catalysts included in the chemical equation of a reaction? Why or why not?
No, they are not included as they are not a reactant that is used in the reaction. They are not a part of the equation itself
17Describe the energy transfer from hydrated copper sulfate to anhydrous copper sulfate + water and vice versa
The same energy is transferred in each case
18When is equilibrium reached? (Define..)
Equilibrium (is reached) when the forward and reverse reactions occur at exactly the same rate. AKA there is no net change in the amount of products + reactants
19What happens when a change is made to a system which is at equilibrium
The system responds to counteract the change.