A-LEVEL CHEMISTRY DEFINITIONS, MODULE 5. Trusted by students across multiple disciplines!

A-LEVEL CHEMISTRY DEFINITIONS, MODULE 5.
Trusted by students across multiple disciplines!
Rate of reaction - Answer: The change in concentration of a reactant or product over
time.


Order - Answer: The power to which the concentration of a reactant is raised in the rate
equation


Overall order - Answer: The sum of all the individual orders


Rate constant - Answer: The constant that links the rate of reaction with the
concentrations of the reactants raised to the powers of their orders in the rate equation


Half-life - Answer: The time taken for the concentration of a reactant to decrease by
half.


Rate-determining step - Answer: The slowest step in the reaction mechanism


Mole fraction - Answer: The mole fraction of gas A in a gas mixture is the number of
moles of gas A divided by the total number of moles of gas


Partial pressure - Answer: The contribution that a gas makes towards the total
pressure.


Bronsted-Lowry acid - Answer: A species that is a proton donor


Bronsted-Lowry base - Answer: A species that is a proton acceptor


Conjugate acid-base pairs - Answer: A pair of species that can be interconverted by
transfer of a proton.


1
APPHIA - Crafted with Care and Precision for Academic Excellence.