Ways Of Measuring Rate Of Reaction Flashcards
What is rate of reaction?
The change in concentration or amount of a reactant or product per unit time
Ways of measuring rate of reaction
Gas volume
Loss of mass
Colour change
Chain in pH
Titration
Electrical conductivity
Gas volume to measure rate of reaction
Collect gas produced in a gas syringe
Record volume of how much is produced in regular time intervals
How to find mol of gas produced in the gas volume method to calculate rate of reaction
We find volume of gas produced in the experiment so use pV = nRT to find number of moles
Then use moles to find conc of gases and it’s change in over time
Loss of mass method to find rate of reaction
Measure mass at regular intervals on balance
Calculate the moles of gas lost based on the difference in mass
So we can use molar ratio to find concentrations and change over time
When can we use the mass lost method to measure the rate of reaction?
If a gas is produced thus the mass will decrease of the reaction vessel
Colour change method to calculate rate of reaction
Take a sample of a reaction at regular intervals
Place in colourimeter to measure absorbance
Compare to calibration curve
Why do we compare to calibration curve once we collect absorbances at regular intervals?
Compare to a calibration curve which has known concentrations to known absorbances so we can find the concentrations of reaction mixture at these intervals of reaction
And so plot a concentration time graph
Changes in ph to measure rate of reaction
Use pH measure meter at regular intervals to measure concentration of H+ ions
Shows change in concentration of H+ ions
Changes in ph to measure rate of reaction
Use pH measure meter at regular intervals to measure concentration of H+ ions
Shows change in concentration of H+ ions
When can we use pH changes to measure rate of reaction?
If the reaction produces or uses up H+ ions
Titration to measure rate of reaction
Take aliquots of a reaction mixture at regular intervals, quench to stop reaction
And Titrate it: using concentration of standard solution we can calculate concentration at this interval
How to quench a reaction?
Dilute with deionised water
Cool down
Use another chemical eg sodium hydrogen carbonate
Using electrical conductivity
Calculate concentration of ions produced if the reaction produces/ uses up ions
Calculated by measuring electrical conductivity of reaction mixture
Concentration time graphs
Using previous methods to find concentration change of a reactant/ product over time at regular intervals
Plot so time = x axis
Concentration = y axis
