Chapter 18 Flashcards
What is the equation for rate of reaction?
change in conc / change in time
What are the units for rate of reaction?
moldm-3s-1
what do square brackets mean?
concentration of …
what is zero order?
when the conc has no effect on the rate
what is zero order?
when the conc has no effect on the rate
what is first order?
when the rate depends on its concentration raised to the power of one
what is first order?
when the rate depends on its concentration raised to the power of one
what is second order?
when the rate depends on its conc raised to the power of 2
what is the rate equation?
rate = k [A]^m [B]^n
what is taking continuous measurements during the course of a reaction called?
Continuous monitoring
What can be used to do continuous monitoring when the product is not a gas?
A colorimeter
what does zero order on a graph look like?
produces a straight line with a negative gradient, the value of the gradient is equal to the rate constant
what does first order look like on a graph?
Produces a downward curve with a decreasing gradient overtime, the half-life is constant
What does second order look like on a graph?
produces a downward curve, steep at the start but tailing off more slowly
What is half-life and its symbol?
t 1/2 : the time taken for half of the reactant to be used up
what is the pattern between first order reactions and half-life?
exponential decay
what measurements are plotted on a rate concentration graph?
The rate of reaction a different concentration
What shape does zero order produce on a rate concentration graph?
A horizontal straight line with zero gradient
what shape does first order produce on a rate concentration graph?
A straight line graph through the origin
what shape does second order produce on a rate concentration graph?
An upward curve with increasing gradient
how do you find the rate constant on a zero order rate concentration graph?
The intercept on the Y axis
how do you determine the rate constant from a first order rate concentration graph?
By measuring the gradient of the straight line
What is the rate determining step?
The slowest step in a sequence of reactions
what happens to the rate constant as temperature increases?
It also increases
