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Flashcards in Defintions Deck (61):
1

Define moles

The amount of any substance containing as many particles as there are carbon atoms in exactly 12 grams of the carbon 12 isotope.

2

Define atom

Positively charged nucleus containing most of the mass, surrounded by atomic shells with orbiting electrons of negative charge and negligible mass.

3

Define isotope

An atom of the same element ​with the same number of protons (electrons) but a different number of neutrons.

4

Define acid

Proton donors. When they’re in water they release H+ ions into the solution.

5

Define alkali

A soluble base which releases OH- ions in solution.

6

Define base

Proton acceptors, they take H+ ions and neutralise acids

7

Define salt

A product of when an H+ ion is replaced by a metal ion.

8

Define anhydrous

A substance containing no water molecules.

9

Define hydrated

A crystalline compound containing water molecules.

10

Define first ionisation energy

The energy required to remove one electron from the outer shell from one mole of gaseous atoms to form one mole of gaseous 1+ ions.

11

Define second ionisation energy

The energy required to remove one electron from the outer shell from one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions.

12

Define nuclear charge

The attraction from the protons in the nucleus with electrons.

13

Define orbital

A region that can hold up to two electrons of opposite spins (Up and down).

14

Define covalent bonding

A bond formed when atoms share pairs of electrons.

15

Define dative covalent bonding

A bond formed when one of the bonding atoms gives both of a pair of electrons.

16

Define electronegativity

The ability of an atom to attract the bonding electrons in a covalent bond.

17

Define relative atomic mass

Average weighted mass of an atom compared with 1/12th of the mass of an atom of Carbon-12.

18

Define relative isotopic mass

Mass of an atom of an isotope compared with 1/12th of the mass of an atom of Carbon-12.

19

Define standard enthalpy of formation

The standard enthalpy change of formation of a compound is the enthalpy change which occurs when one mole of the compound is formed from its elements under standard conditions, and with everything in its standard state.

20

Define standard enthalpy of combustion

The standard enthalpy change of combustion of a compound is the enthalpy change which occurs when one mole of the compound is burned completely in oxygen under standard conditions, and with everything in its standard state.

21

Define standard enthalpy of neutralisation

The standard enthalpy change of neutralisation is the enthalpy change when solutions of an acid and an alkali react together under standard conditions to produce 1 mole of water.

22

Define standard enthalpy of reaction

The standard enthalpy change is the enthalpy change that occurs in a reaction in molar quantities shown in a chemical equation under standard conditions.

23

Define average bond enthalpy

The energy required to break one mole of a specified type of bond in a gaseous molecule.

24

Define Hess' law

If a reaction can take place by two routes and the starting and finishing conditions are the same, the total enthalpy change is the same for each route.

25

Define activation energy

The minimum energy required for a reaction to occur.

26

Define specific heat capacity

The energy required to raise the temperature of 1 gram of a substance by 1 Kelvin.

27

Define electrophile

It is an electron pair acceptor.

28

Define nuclearphile

It is an electron pair donor.

29

Define ionic bond

Oppositely charged ions held together in a crystal lattice by electrostatic attraction.

30

Define lattice enthalpy

The enthalpy change that occurs when 1 mole of a solid ionic compound is formed from its gaseous ions under standard conditions.

31

Define standard enthalpy of solution

The enthalpy change that occurs when 1 mole of solute is completely dissolved in the solvent under standard conditions.

32

Define standard enthalpy of hydration

The enthalpy change that occurs when 1 mole of isolated gaseous ions are dissolved in water forming 1 mole of aqueous ions under standard conditions.

33

Define transition element

A metal atom with partially filled d orbitals as it forms an ion.

34

Define ligand

An atom/molecule/ion that can donate a pair of electrons to a metal ion to form a dative covalent bond.

35

Define buffer solution

A system, containing a weak acid and its conjugate base, that minimises pH change when a small amount of acid/alkali is added.

36

Define monomer

Small molecules that are part of a long chain of monomers.

37

Define polymer

Long chain molecules with monomers joined together.

38

Define addition polymerisation

The formation of a large chain of monomers through the rearrangement of bonds of smaller monomers.

39

Define condensation polymerisation

The formation of one large polymer from many small monomer molecules joining together, with water, or some other small molecule formed at the same time.

40

Define stereoisomerism

Same structural formula but different arrangement in space.

41

Define enantiomer

The optical isomer of the same molecule.

42

Define catalyst

A substance that increases the rate of a chemical reaction by providing alternate routes without itself undergoing any permanent chemical change.

43

Define homogeneous equilibrium

The reactants and products at equilibrium are all in the same state.

44

Define heterogeneous equilibrium

The reactants and products are in different states.

45

Define the equivalence point of titration

The volume of one substance that exactly reacts with another.

46

Define the end point of a titration

Concentrations of HA and A are equal.

47

Define standard electrode potential

The potential difference of a half cell compared with a standard hydrogen half cell, measured at 298K with solution concentrations of 1 mol dm^-3 and a gas pressure of 100kPa

48

Define zwitterion

A molecule/ion that has separate groups of negative and positive charge.

49

Define isoelectric point

The pH at which zwitterion exists.

50

Define optical isomerism

Non-superimposable mirror images of the same molecule.

51

Define molecular ion

An unfragmented ion with positive charge.

52

Define radical

A molecule that contains at least one unpaired electron.

53

Define spin-spin coupling

When the hydrogen peak is split from the influence of hydrogen atoms attached to the neighbouring carbons.

54

Define complex ion

A metal ion at the centre with a number of other molecules or ions surrounding it attached to the central ion by co-ordinate (dative covalent) bonds.

55

Define functional group

A part of an organic molecule that is largely responsible for the molecule's chemical properties.

56

Define empirical formula

The simplest whole number ratio of atoms of each element present in a compound

57

Define molecular formula

The number and type of atoms of each element in a molecule

58

Define general formula

The simplest algebraic formula for any member of the homologous series

59

Define homologous series

A series of compounds with the same functional group and similar chemical properties.

60

Define homolytic fission

A chemical reaction in which the breaking of bonds yields molecular fragments each having one unpaired electron.

61

Define heterolytic fission

A chemical reaction in which the breaking of bonds leads to the formation of ion pairs.