2.1 Flashcards
What is the initial rate of reaction?
The change in concentration of a reactant, or product, per unit time at the start of a reaction when t=0.
What is the rate equation for a reaction A + B»_space;> C?
Rate = k[A][B]
What is the half life of a reactant?
The time taken for the concentration of the reactant to reduce by half.
What is the rate determining step?
The slowest step in the reaction mechanism of a multi step reaction.
What is an intermediate?
A species formed in one step of a multi step reaction that is used up in a subsequent step, and is not seen as either a reactant or a product of the overall equation.
What is the rate of reaction?
The change in concentration of a reactant or product per unit time.
What is an order with respect to a reactant?
The power to which the concentration of the reactant is raised in the rate equation.
What is the overall order of a reaction?
The sum of the individual orders.
What is the rate constant, K?
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.
What is a reaction mechanism?
A series of steps that make up the overall equation.
What is dynamic equilibrium?
Exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction.
What is a homogeneous equilibrium?
An equilibrium in which all the species making up the reactants and products are in the same physical state.
What is a heterogeneous equilibrium?
An equilibrium in which species making up the reactants and products are in different physical states.
What is a Brønsted-Lowry acid?
A proton donor.
What is a Brønsted-Lowry base?
A proton acceptor.
What is an alkali?
A base that dissolves in water forming OH- ions.
What is neutralisation?
A chemical reaction in which an acid and a base react together to produce a salt and water.
What is an acid-base pair?
A pair of two species that transform into each other by gain or loss of a proton.
What is the calculation for pH?
-log[H+]
What is the calculation for [H+]?
10^-pH
What is a strong acid?
An acid that completely dissociates in solution.
What is a weak acid?
An acid that partially dissociates in solution.
What is Ka?
The acid dissociation constant.
Ka = ([H+][A-])➗[HA]
What is pKa?
-log(Ka)
What is Ka (in terms of pKa)?
10^-pKa
What is Kw?
The ionic product of water.
Kw = [H+][OH-] = at 25 degrees Celsius, 10^-14 mol2 dm-6
What is a buffer solution?
A mixture that minimises pH changes on addition of small amounts of acid or base.
What is the equivalence point?
The point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution.
What is the end point?
The point in a titration at which there are equal concentrations of the weak acid and conjugate base forms of the indicator.
What is the standard enthalpy change of neutralisation?
The energy change that accompanies the neutralisation of an aqueous acid by an aqueous base to form one mole of water, under standard conditions.
