OCR Chemi unit 5 definitions

?
Rate of reaction
is the change in concentration of a reactant or product per unit of time
1 of 50
Initial rate of reaction
is the change in concentration of a reactant or product per unit of time at the start of the reaction when t=0
2 of 50
th order with respect to a reactant
is the power to which the concentration of the reactant is raised in the rate equation
3 of 50
the rate constant, k,
is the constant that links the rate of reaction with the concentration of the reactants raised to the powers of their orders in the rate equation
4 of 50
the half-life
of a reactant is the time taken for the concentration of the reactant to reduce by half
5 of 50
a reaction mechanism
is a series of steps that together, make up the overall reaction
6 of 50
the rate determining step
is the slowest step in the reaction reaction mechanism of a multi-step reaction
7 of 50
an intermediate
is 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 reaction
8 of 50
Equilibrium law
states that for the equilibrium
9 of 50
a dynamic equilibrium
exists in a closed system when rate of the forward reaction is equal to the rate of the backwards reaction
10 of 50
a homogeneous equilibrium
is an equilibrium in which all the species making up the reactants and products are in the same state
11 of 50
a heterogeneous equilibrium
is an equilibrium in which species making up the reactants and products are in different physical states
12 of 50
Bonsted-Lowry acid
is a proton, H+, donor
13 of 50
Bronsted-Lowry base
is a proton, H+ acceptor
14 of 50
an alkinli
is a base that dissolves in water forming OH- (aq) ions
15 of 50
Neutralisation
is a chemical reaction in which an acid and a base react together to produce a salt and water
16 of 50
An acid-base pair
is a pair of two species that transform into each other by gain or loss of a proton
17 of 50
pH
=log[H+(aq)]
18 of 50
[H+(aq)]
= 10
19 of 50
A strong acid
is an acid that completely dissociates in solution
20 of 50
a weak acid
is an acid that only partially dissociates in solution
21 of 50
pK
=-log K
22 of 50
K
=10
23 of 50
a buffer solution
is a mixture that minimises pH changes on addition of small amounts of acid or base
24 of 50
the equivalence point
is the point in a titration at which the volume of one solution has reacted exactly with the volume of the second solution. This matched the stoichiometry of the reaction taking place
25 of 50
end point
is the point in a titration at 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
26 of 50
the standard enthalpy change of neutralisation
is the energy change that accompanies the neutralisation of an aqueous acid by an aqueous base to form one mole of H O(l) under standard conditions
27 of 50
Lattice enthalpy
is the enthalpy change that accompanies the formation of one mole of an ionic of an ionic compound from its gaseous ions under standard conditions
28 of 50
Hess' Law
states that if a reaction can take place by more than one route and the initial and final conditions are the same, the total enthalpy change is the same for each route.
29 of 50
standard enthalpy change of formation
is the enthalpy change that takes place when one mole of a compound is formed from its constituent elements in their standard states under standard conditions
30 of 50
enthalpy change of atomisation
is the enthalpy change that takes place when one mole of gaseous atoms forms from the element in its standard state
31 of 50
first ionisation energy
is the enthalpy change accompanying the removal of one electron from each atom in one mole of gaseous atoms to for one mole of gaseous 1+ ions
32 of 50
second ionisation energy
is the enthalpy change accompanying the removal of one electron from each atom in one mole of gaseous 1+ ions to for one mole of gaseous 2+ ions
33 of 50
first electron affinity
is the enthalpy change accompanying the addition of on electron to each atom in one mole of gaseous atoms to form one mole of gaseous 1- ions
34 of 50
second electron affinity
is the enthalpy change accompanying the addition of on electron to each atom in one mole of gaseous 1- ions to form one mole of gaseous 2- ions
35 of 50
standard enthalpy of solution
is the enthalpy change that takes place when one mole of a compound is completely dissolved in water under standard conditions
36 of 50
standard enthalpy change of hydration
is the enthalpy change that takes place when one mole of isolated gaseous ions is dissolved in water forming one mole of aqueous ions under standard conditions
37 of 50
entropy, S,
is the quantitative measure of the degree of disorder in a system
38 of 50
standard entropy change of reaction, S ,
is the entropy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactants and products being in their standard states
39 of 50
free energy change
is the balance between enthalpy, entropy and temperature for a process:
40 of 50
oxidation
is the loss of electrons, or an increase in oxidation number
41 of 50
reduction
is the gain of electrons, or a decrease in the oxidation number
42 of 50
standard electrode potential of a half cell
is the e.m.f of a half cell compared with a standard hydrogen half cell, measured at 298K with solution concentrations of 1 mol dm and a gas pressure of 100kPa
43 of 50
transition element
is a d block elements that forms an ion with a incomplete d sub shell
44 of 50
a complex ion
is a transition metal ion bonded to one of more ligands by coordinate bonds (dative covalent bonds)
45 of 50
ligand
is a molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond
46 of 50
coordination number
os the total number of coordinate bonds formed between a central metal ion and its ligands
47 of 50
sterioisomers
are species with the same structural formula but with a different arrangement of the atoms in space
48 of 50
ligand substitution
is a reaction in which one ligand in a complex ion is replaced by another ligand
49 of 50
stability constant, K
is the equilibrium constant existing between a transition metal ion surrounded by water ligands and the complex formed when the same ion has undergone a ligand substitution
50 of 50

Other cards in this set

Card 2

Front

Initial rate of reaction

Back

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

Card 3

Front

th order with respect to a reactant

Back

Preview of the front of card 3

Card 4

Front

the rate constant, k,

Back

Preview of the front of card 4

Card 5

Front

the half-life

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »