# F325 Definitions

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• Created by: Lottie
• Created on: 06-01-14 10:57
Rate of Reaction
The change in concentration of a reactant or product per unit time
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Initial Rate of Reaction
The change in concentration of a reactant, or product, per unit time at the start of the reaction when t=0
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Rate Equation
For a reaction: A + B --> C, rate equation is given by: rate = k [A]^m [B]^n, where m=order of reaction with respect to A and n=order of reaction with respect to B.
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Order
The power to which the concentration of a reactant is raised in the rate equation
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Overall Order
The sum of the individual orders, m + n
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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
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Half-life
The time taken for the concentration of the reactant to reduce by half
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Reaction Mechanism
A series of steps that, together, make up the overall reaction
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Rate-determining Step
The slowest step in the reaction mechanism of a multi-step reaction
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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 in the overall equation
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Equilibrium Law
For the equilibrium: aA + bB --> cC + dD, Kc = [C]^c [D]^d / [A]^a [B]^b
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Dynamic Equilibrium
The equilibrium that exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction
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Homogeneous Equilibrium
An equilibrium in which all the species making up the reactants and products are in the same physical state
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Heterogeneous Equilibrium
An equilibrium in which species making up the reactants and products are in different physical states
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Brønsted-Lowry Acid
A proton, H+, donor
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Brønsted-Lowry Base
A proton, H+, acceptor
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Alkali
A base that dissolves in water forming OH-(aq) ions
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Neutralisation
A chemical reaction in which an acid and a base react together to produce a salt and water
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Acid-base Pair
A pair of two species that transform into each other by gain or loss of a proton
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pH
-log [H+ (aq)]
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[H+(aq)]
10^-pH
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Strong Acid
An acid that completely dissociates in solution
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Weak Acid
An acid that partially dissociates in solution
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Acid Dissociation Constant, Ka
Acid dissociation constant for an acid, HA: Ka = [H+ (aq)] [A- (aq)] / [HA (aq)]
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pKa
-log Ka
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Ka
10^-pKa
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Ionic Product of Water, Kw
Kw = [H+ (aq)] [OH- (aq)] **At 25°C, Kw = 1.00x10^-14 mol^2 dm^-6
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Buffer Solution
A mixture that minimises pH changes on addition of small amounts of acid or base
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Equivalence Point
The point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution. This matches the stoichiometry of the reaction taking place
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End Point
The point in a titration at which which there are equal concentrations of the weak acid and conjugate base forms of the indicator. The colour at the end point is midway between the colours of the acid and conjugate base forms
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## Other cards in this set

### Card 2

#### Front

The change in concentration of a reactant, or product, per unit time at the start of the reaction when t=0

#### Back

Initial Rate of Reaction

### Card 3

#### Front

For a reaction: A + B --> C, rate equation is given by: rate = k [A]^m [B]^n, where m=order of reaction with respect to A and n=order of reaction with respect to B.

### Card 4

#### Front

The power to which the concentration of a reactant is raised in the rate equation

### Card 5

#### Front

The sum of the individual orders, m + n

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