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Chemistry Unit 1 AS > Definitions > Flashcards

Definitions Flashcards

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0
Q

Ionic bond

A

the electrostatic attraction between positive ions and negative ions

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1
Q

Relative Isotopic Mass

A

the mass of an atom of an isotope compared with one-twelfth of the mass of an atom of carbon-12

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2
Q

Salt

A

ionic compound formed from an acid when a H+ ion from acid had been replaced by a metal ion or another positive ion

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3
Q

Isotopes

A

atoms of the same element with the same number of protons but different numbers of neutrons and so different masses

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4
Q

relative atomic mass

A

the weighted mean mass of an atom of an element compared to one-twelfth of the mass of an atom of carbon-12

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5
Q

Avogadro’s constant

A

the number of atoms/particles per mole of a substance (of the carbon-12 isotope)
6.02 x10*23

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6
Q

relative molecular mass

A

weighted mean mass of a molecule compared with one-twelfth of the mass of an atom of carbon-12

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7
Q

mole

A

the amount of any substance containing as many particles as there are carbon atoms in exactly 12g of the carbon-12 isotope

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8
Q

relative formula mass

A

weighted mean mass of a formula unit compared with one-twelfth of the mass of an atom of carbon-12

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9
Q

molar mass

A

the mass per mole of a substance - gmol-1

can find it by adding all RAMs for each atom in the formula

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10
Q

avogadros hypothesis

A

equal volumes of gases at the same temperature and pressure contain equal numbers of molecules

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11
Q

molar volume

A

volume per mole of gas molecules - dm3mol-1

at RTP molar vol is approx 24.0dm3mol-1

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12
Q

concentration of a solution

A

the amount of solute, in mol, dissolved per 1dm3 of solution

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13
Q

standard solution

A

a solution of a known concentration normally used in titrations to determine unknown info about another substance

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14
Q

conc (moldm-3) =

A

moles/volume

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15
Q

conc (gdm-3) =

A

mass/volume

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16
Q

no. moles of a gas=

A

volume/24

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17
Q

empirical formula

A

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

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18
Q

molecular formula

A

the actual numbet of atoms of each element in a molecule

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19
Q

molecule

A

small group of atoms held together by covalent bonds

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20
Q

what colour is methyl orange indicator in

a) acid
b) base
c) endpoint

A

a) red
b) yellow
c) orange

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21
Q

what colour is phenolphthalein indicator in

a) acid
b) base
c) endpoint

A

a) colourless
b) pink
c) pale pink

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22
Q

what is the colour of bromothymol blue indicator in

a) acid
b) base
c) endpoint

A

a) yellow
b) blue
c) green

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23
Q

acid

A

a species that is a proton donor

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24
Q

base

A

species that is a proton acceptor

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25
Q

alkali

A

soluble base in water forming hydroxide ions

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26
Q

cation

A

positively charged ion

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27
Q

hydrated salt

A

crystalline compound containing water molecules

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28
Q

anion

A

negatively charged ion

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29
Q

anhydrous salt

A

substance that contains no water molecules -

the form without water

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30
Q

water of crystallisation

A

water molecules that form an essential part of the crystalline structure of a compound

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31
Q

species

A

any type of particle that takes place in a chemical reaction

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32
Q

oxidisation number

A

a measure of the number of electrons that an atom uses to bond with atoms of another element

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33
Q

oxidisation no for ‘uncombinded element’

A

0

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34
Q

oxididation no for ‘combined oxygen’

A

-2

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35
Q

oxidiation no for ‘combined hydrogen’

A

+1

36
Q

oxidation no for ‘combined fluorine’

A

-1

37
Q

oxyanions

A

negative ions that contain an element along with oxygen

38
Q

oxidation

A

loss of electrons or an increase in oxidation numbet

39
Q

reduction

A

gain of electrons or a decrease in oxidation number

40
Q

redox reaction

A

reaction where both reduction and oxidation happen

41
Q

first ionisation energy of an element

A

the energy required to remove 1 electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

42
Q

electron sheilding

A

the repulsion between electrons in different inner shells. Sheilding reduces the net attractive force from the positive nucleus on outer-shell electrons

43
Q

successive ionisation energy

A

a measure of the energy required to remove each electron in turn from 1 mole of gaseous atoms

44
Q

shell

A

group of atomic orbitals with the same principal quantum number, n. Also known as main energy level

45
Q

sub-shell

A

group of the same type of atomic orbitals (s,p,d and f) within a shell

46
Q

orbital

A

region, or volume of space, within an atom that can hold up to 2 electrons with, opposite spins

47
Q

electron configuration

A

arrangement of electrons in an atom

48
Q

compound

A

a substance formed when 2 or more different elements chemically bond together in a fixed ratio

49
Q

ionic bond

A

the electrostatic attraction between oppositely charged ions

50
Q

covalent bond

A

bond formed by a shared pair of electrons

51
Q

giant ionic lattice

A

3-D structure of oppositely charged ions bonded together by strong electrosatic forces

52
Q

lone pair

A

the outer-shell pair of electrons that is not involved in chemical bonding

53
Q

bond pairs

A

pairs of electrons that are shared between 2 atoms

54
Q

dative covalent or coordinate bond

A

a shared pair electrons where both of the electrons have been provided by one of the bonding atoms only

55
Q

trigonal planer

A

bond angle= 120

3bp 0lp

56
Q

linear

A

bond angle = 180

2bp 0lp

can have double bonds but ignore and pretend ‘ 2 bonding regions’

57
Q

tetrahedral

A

bond angle = 109.5

4bp 0lp

58
Q

octahedral

A

bond angle = 90

6bp 0lp

59
Q

pyradimal

A

bond angle = 107

3bp 1lp

60
Q

non-linear

A

104.5 bond angle

2bp 2lp

61
Q

electronegativity

A

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

measure of attraction of a bonded atom for the pair of electrons in a covalent bond

62
Q

permanent dipole

A

a small charge difference across a bond that results from a difference in the electronegativities of the bonded atoms

63
Q

polar covalent bond

A

has a permanent dipole

64
Q

how does a permanent dipole arise

A

when covalently-bonded atoms have different electronegativities, resulting in a polar bond

65
Q

polar molecule

A

has an overall dipole, when you take into account any dipoles across the bonds

66
Q

the greater the difference between the electronegativities of the bonding atoms….

A

the greater the ionic character of the bond

67
Q

the greater the similarity in electronegativities of the bonding atoms….

A

the greater the covalent character of the bond

68
Q

internolecular force

A

attractive force between neighboring molecules

69
Q

permanent dipole-dipole force

A

a weak attractive force between PERMANENT DIPOLES in neighboring polar molecules

70
Q

van der waals forces

A

attractive forces between INDUCED DIPOLES in neighbouring molecules

71
Q

hydrogen bond

A

strong dipole-dipole attraction between:

  • an electron-deficient hydrogen atom (O or N) on one molecules
  • a lone pair of electrons on a highly electronegative atom (H-O or H-N) on a DIFFERENT MOLECULE
72
Q

special properties of water

A
  • ice is less dense than water (ice floats)

- water has relatively high melting and boiling points than expected for a small molecule

73
Q

metallic bonding

A

electrostatic attraction between positive metal ions and negative delocalised electrons

74
Q

delocalised electrons in metallic bonding

A

shared between more than 2 atoms

75
Q

giant metallic lattice

A

a 3D structure of positive ions and delocalised electrons bonded together by strong metallic bonds

76
Q

simple molecular lattice

A

3D structure of molecules, bonded together by weak IMF

77
Q

giant covalent lattice

A

3D structure of atoms, bonded together by strong covalent bonds

78
Q

period

A

horizontal row of elements in the Periodic Table - elements show trends in properties across a period

79
Q

group

A

vertical column in Periodic Table. Elements in a group have similar chemical properties and their atoms have the same number of outer-shell electrons

80
Q

periodicity

A

regular periodic variation of properties of elements with atomic number and position in Periodic Table.

REPEATING PATTERN ACROSS DIFFERENT PERIODS

81
Q

across a period what is the most important factor influencing ionisation energy

A

increased nuclear charge

82
Q

down a group what is the most important factors influencing ionisation energy

A

increase distance and sheilding

83
Q

thermal decomposition

A

breaking up of a chemical substance with heat into at least

two chemical substances

84
Q

displacement reaction

A

a reaction in which a more-reactive element displaces a less-reactive element from an aqueous solution of the latter’s ions

85
Q

disproportionation

A

reaction in which an element is simultaneously oxidised and reduced as a redox reaction

86
Q

precipitation reaction

A

formation of an insoluble solid from 2 solutions in a chemical reaction

87
Q

atom

A

smallest particle of an element that retains its chemical properties

Chemistry Unit 1 AS (3 decks)

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