Module 5 Chapter 18
No description yet. This curated deck is ready for daily study.
Card preview (24)
What is required for a reaction to take place
particles must collide before a reaction can take place The reactants must possess at least the minimum amount of energy - activation energy Particles must approach each other in a certain relative way - the STERIC EFFECT
What is the rate of reaction proportional to
The concentration of a particular reactant raised to a power
What is the power called
The order of the reaction for that reactant
What are the powers for the different orders
N = 0 zero order N = 1 first order N = 2 second order
What is order
The order attributed to a reagent identifies the effect changing its concentration has on rate of a reaction
What is the rate constant k
It is a constant of proportionality that reflects the ease that a reaction takes place. Where larger values of k result in a greater rate of reaction.
What does the continuous monitoring method allow
Data to be collected through the course of the reaction —> allowing data to be plotted on a. Concentration tie graph
What does calorimetry allow
The measurement of the absorption of light passing through a coloured solution
What can be done with the absorption of the coloured solution
A calibration curve made from known concentration can then be used to determine the concentration at a given time
How is a calorimetry experiment done (1)
• a reaction with an observable colour change must be used • You must then zero the colorimeter, in order to create a calibration curve. Which is done by using known concentrations of the species responsible for the observable colour change. Allowing you to convert absorbance readings into concentration readings later • Carry out the reaction between your reactants taking absorbance measurements at regular time intervals.
How is a calorimetry experiment done (2)
Compare the absorbance values against the calibration curve from earlier - extrapolating the concentration at these times Plot concentration against time, which can then be used to determine order of reaction
What can you use concentration time graphs to determine
The rate from the gradient The order from the shape of the curve
What does a first order concentration time graph look like
It is a downward curve Rate is decreasing
What does a second order concentration time graph look like
Similar to the first order curve But it starts steeper and tails of slower
What is the half life of a reaction
The time it takes for the concentration to decrease by half
What is a feature of the half life of a first order reaction
They have a constant half life and an exponential decay
What is the formula you use to determine k for a first order reactant
k = ln2/t 1/2
What is the rate concentration graph for a zero order reactant
DRAW IT
What is the rate concentration graph for a first order reactant
DRAW IT
What is the rate concentration graph for a second order reactant
Draw it
What is the rate equivalent to for a zero order reactant
K
What is the rate equivalent to for a first order reactant
Rate = k[A]
What is the rate equivalent to for a second order reactant
Rate = k[A]^2
What is a feature of the rate second order rate concentration graph
K can’t be determined from this graph unless it’s re plotted as rate against concentration squared