Rates of reaction Flashcards
The rate at any point in the reaction is given by the ________ at that point on the graph.
gradient
If you double the reactant and this has no effect on the rate, the order with respect to that reactant is ____.
zero
If you double the reactant and this quadruples the rate, the order with respect to that reactant is ____.
two
If you double the reactant and this increases the rate by n-fold, the general expression for the order with respect to that reactant is ____.
log₂n
For a reactant whose ([X],rate) graph is a horizontal line, what is the order?
Zero
For a reactant whose ([X],rate) graph is linear, going through the origin, what is the order?
One
For a reactant whose ([X],rate) graph is a curve, what is the order?
Two (or higher depending upon the shape of the curve)
Outline three methods of measuring the rate of a reaction.
Measurement of gas volume; track colour change in a reaction using a colorimeter; measure electrical conductivity (all these would be measured at regular time intervals)
Define the initial rate of reaction.
The rate of reaction (i.e. gradient of tangent) at t=0, right at the beginning of the reaction
What type of reactions allow easy measurement of initial reaction rate?
Clock reactions; because they repeat, and you can easily measure the time needed for the reaction as it is usually accompanied by a sudden colour change
Define half-life.
The time taken for the concentration of a reactant to be halved/half of the reactant to be used up
The half-life of a first order reaction is ___________ of the concentration.
independent
For a general reaction aA + bB + dD → eE + fF where only reactants A and D are involved in the rate determining step, express the rate.
Rate = k[A]ᵃ[D]ᵈ
The value of the rate constant is specific to which of the conditions the reaction ocurrs in?
Temperature
Define rate determining step.
The slowest step in a multi step reaction mechanism.
