Ib Chemistry

Front 1

Activation energy

Back 1

minimum amount of energy required for a chemical reaction

Front 2

Covalent bond

Back 2

electrostatic attraction between a pair of electrons and +vly charged nuclei

Front 3

Atomic number

Back 3

number of protons in the nucleus

Front 4

Enthalpy change

Back 4

H(products) - H(reactants)

Front 5

Standard electrode potential

Back 5

potential of a half-reaction under standard conditions, as measured against potential of standard hydrogen electrode

Front 6

Solution

Back 6

A homogeneous solution comprised of one or more solutes dissolved in a solvent

Front 7

Solvent

Back 7

dissolving medium in a solution

Front 8

Acids and bases according to Lewis theory

Back 8

acid: electron pair acceptor.
base: electron pair donor.

Front 9

Buffer solution

Back 9

aqueous solution that resists changes in pH when small amount of acid, base or water are added

Front 10

Acids and bases according to Bonsted-Lowry theory

Back 10

Acids: proton donor
Bases: proton acceptor

Front 11

Enthalpy

Back 11

Heat energy converted from energy in chemical bonds

Front 12

Standard enthalpy change

Back 12

enthalpy change when molar quantities of reactants in normal state react to form products in normal state under standard conditions (298K, 101.3kPa or 1atm)

Front 13

Oxidizing agent

Back 13

A substance that is able to oxidize other substances.
agent itself undergoes reduction

Front 14

Ionic bond

Back 14

Electrostatic attraction between oppositely charged ions

Front 15

Rate of reaction

Back 15

change in concentration of a reactant or product per unit of time

Front 16

Isotopes

Back 16

Atoms of same element with different number of neutrons

Front 17

Reducing agent

Back 17

Able to reduce other substances
- undergoes oxidation

Front 18

Mass number

Back 18

Sum of atom's protons and neutrons

Front 19

Solute

Back 19

a substance dissolved in liquid to form a solution

Front 20

Concentration

Back 20

1cm³ = 1ml
1000cm³ = 1dm³ = 1L
g/L = g x dm-³
molarity = mol/L = M = mol x dm-³

Front 21

Describe features of a homologous series

Back 21

-Same general formula (CnH2n)
-differ by methyl group
-similar chemical properties
-gradually changing physical properties (viscosity, temp etc.)

Front 22

Define Molecular mass

Back 22

Sum of relative atomic masses of a given molecule

Front 23

Average bond enthalpy

Back 23

energy change when 1 mol of covalent bond in gaseous state is formed from gaseous atoms

Front 24

Relative atomic mass

Back 24

weighted average of atomic masses of all naturally occurring isotopes of an element

Front 25

Delocalized electrons

Back 25

valence electrons that are detached from the atoms so they are free to move around

Front 26

Standard Hydrogen Electrode

Back 26

platinum electrode
hydrogen gas at 1 atm
aqueous solution of acid H + ions = 1M
temperature = 298K

Front 27

Lattice enthalpy

Back 27

enthalpy change when an ionic salt is formed from gaseous ions under standard conditions

Front 28

Oxidation

Back 28

Loss of electrons from one or more substance

Front 29

Reduction

Back 29

Gain of electrons from one or more substance

Front 30

Standard enthalpy change of combustion

Back 30

change in enthalpy that accompanies formation of one mole of compound from its complete reaction with oxygen gas

Front 31

Standard enthalpy change of formation

Back 31

change in enthalpy that accompanies the formation of one mole of compound from its elements

Front 32

Exothermic reaction

Back 32

releases heat to surroundings

Front 33

Electron affinity

Back 33

enthalpy change associated with the addition of an electron to a gaseous ion

Front 34

First ionization energy

Back 34

energy required to remove one electron from an atom in gaseous state

Front 35

Electronegativity

Back 35

a measure of an atom's ability to attract a bonding pair of electrons to itself

Front 36

Ligand

Back 36

neutral molecules or negative ions that contain a non-bonding pair of electrons

Front 37

Endothermic reaction

Back 37

absorbs heat from surroundings

Front 38

Standard state

Back 38

Temperature of 25°C, 298K
Pressure of 1 atm
Liquids and solids are pure
Aqueous solutions are 1M