Rates of Reaction Flashcards
rate of a chemical reaction definition
the speed at which the raction occurs
the speed at which the reactants are used or products are produced
How many ways can rates be measured?
7
List all the ways rates can be measured
- change in mass of reactnats/products
- concentration
- change in pH (acids/bases)
- change in conductivity (ion production)
- change in colour
- change in temperature
- change in colume or pressure ( for gasses only)
how does rate and slope relate?
rate = -slope
average rate of reaction definition
the change in concentration in a gicen time period
how is rate expressed?
in terms of the amount of a product produced or the amount of a reactant consumed
effective collisions definition
particles collide and it resutls in the formation of a product
What is needed for an effective collision?
- must occur at correct orientation
- must have a minimum amount of energy
collision model
the idea of effective collisions - the rate of a reaction is affected by the number of effective collisions between reactant molecules
according to the collision model how can the rate of reaction be increased?
increasing the number of collisions or by increasing the number of effective collisions
activation energy definition
the minimum amount of potential energy required for a reaction to occur
how does low activation energy relate to rate of reaction?
greater rate of reaction
how do catalysts increase the rate of reaction?
provides an alternative pathway with a lower activation energy
what is the theoretical effect (what they do) of catalysts?
- bends/stretches bonds to make them easier to break /react
- bring to reactants closer together
- provides a microenvironment for reactions
what are the types of catalysts?
- homogenous catalysts
- heterogenous catalysts
what is a homogenous catalyst?
the catalyst exists in the same phase as the reactants
what are homogenous catalysts most often?
they often catalyze gaseous and aqeous reactions
what is heterogenous catalyst?
the catalyst exists in a different phase from the reactants
what is an inhibitor?
something that decreases the rate of a reaction when added -> interferes with the catalyst
how does the inhibitor work?
bonds to the catalyst instead of the reactant
threshold energy
the amount of energy needed for the reaction to happen
rate law definition
describes the relationship between the rate of the product and the initial concentrations of the reactants
what is an elementary reaction?
a reaction that only occurs in one step
orders of reaction
the exponents in the rate law equation
