Y12 Definitions

Question 1

Relative isotopic mass

Answer 1

The mass of an isotope relative to 1/12 of the mass of carbon 12

Question 2

Relative atomic mass

Answer 2

The weighted mean mass of an element relative to 1/12 of the mass of carbon 12

Question 3

Ammonium

Answer 3

NH4+

Question 4

Hydroxide

Answer 4

Oh-

Question 5

Nitrate

Answer 5

NO3-

Question 6

Nitrite

Answer 6

NO2-

Question 7

Hydrogen carbonate

Answer 7

HCO3-

Question 8

Manganite VII

Answer 8

MnO4-

Question 9

Carbonate

Answer 9

CO32-

Question 10

Sulphate

Answer 10

SO42-

Question 11

Sulfite

Answer 11

SO32-

Question 12

Dichromate VI

Answer 12

Cr2O72-

Question 13

Phosphate

Answer 13

PO43-

Question 14

Polyatomic molecules

Answer 14

N2 P4 S8

Question 15

Mole

Answer 15

The amount of substance that contains 6.02 x10^23 particles

Question 16

Molar mass

Answer 16

Mass per mole of a substance units are gmol^-1

Question 17

Molecular formula

Answer 17

The actual number of atoms of each element in a molecule

Question 18

Empirical formula

Answer 18

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

Question 19

Relative molecular mass

Answer 19

Compares the mass of the molecule with the mass of an atom of carbon 12 calculated by adding atomic masses together

Question 20

Relative formula mass

Answer 20

Compares the mass of the formula unit with the mass of an atom of carbon 12 calculated by adding together the relative atomic masses of the elements in the empirical formula

Question 21

Molecular formula

Answer 21

Molecular mass divided by empirical formula mass

Question 22

Room temperature and pressure

Answer 22

20°C 101KPA or one atmosphere

Question 23

Ideal gas equation

Answer 23

PV= nRT
P= pressure Pa
V= volume m^3= 1000dm^3
n= moles
R= gas constant= 8.31j/mol/k
T=temp= K

Question 24

Assumptions real gas equation

Answer 24

Random motion elastic collisions negligible size no intermolecular forces

Question 25

Stoichiometry

Answer 25

The ratio balancing an equation

Question 26

Atom economy

Answer 26

A measure of how well the atoms have been utilised Reactions with high at McConomy is produced a large proportion of desired product few unwonted waste products they are important the sustainability and make the best use of natural resources based on balanced chemical equations assume 100% yield atom economy equals some of mola masses of desired Products divided by some of mola masses of all products times 100

Question 27

Bases

Answer 27

Metal oxides metal hydroxide metal carbonate and ammonia NH3

Question 28

Alkalis

Answer 28

A base the dissolves in water releasing hydroxide ions into the solution

Question 29

Acid plus base

Answer 29

Salt and water

Question 30

Dissociation of sulphuric acid

Answer 30

Only one of the two hydrogen atoms is a strong acid's are only partially dissociates to form HSO4- This then disassociates to form SO42-

Question 31

Titrations

Answer 31

Technique used to accurately measure the volume of one solution that reacts with another solution

Question 32

Ox number F

Answer 32

-1

Question 33

Special cases oxidation number is

Answer 33

H in metal hydrides(NaH)= -1 O in peroxide = -1 O bonded to F= +2

Question 34

Max no of electrons in a shell

Answer 34

2n^2

Question 35

Atomic orbitals

Answer 35

A region around the nucleus that can hold up to 2 electrons with opposite spins

Question 36

Patterns of 4S and 3-D subs shells

Answer 36

4S fills before 3-D and empties before as once fills 3-D energy levels fall below 4S energy levels

Question 37

Covalent bond

Answer 37

Strong electrostatic attraction between shared pair of electrons and the nuclei of the bonded atoms

Question 38

Boron bond forming

Answer 38

Boring has three electrons in outershell when all three are bonded in covalent bonding only six electrons are in its outer shell

Question 39

Expanding the octad

Answer 39

Occurs after the third shell depends how many unpaired electrons

Question 40

Dative covalent bonds

Answer 40

Form when there is originally a lone pair of electrons on one of the bonded atoms for example ammonium is formed when an ammonia and hydrogen ions react

Question 41

2 electron regions

Answer 41

Linear bond angle 180° example CO2

Question 42

Three electron regions

Answer 42

Trogonal planar Bond angle 120° example BF3

Question 43

4 electronic regions

Answer 43

Tetrahedral bond angle 109.5°CH4

Question 44

Six electron regions

Answer 44

Octahedral 90° SF6

Question 45

Electronegativity

Answer 45

The attraction of a bonded atoms for the pair of electrons in a covalent bond

Question 46

Intermolecular forces

Answer 46

Week interactions between dipoles of different molecules

Question 47

London forces

Answer 47

Induced dipole dipole interactions

Question 48

Simple molecular substance

Answer 48

Made up of simple molecules small units containing definite number of atoms with a definite molecular formula such as H2O CO2 H2

Question 49

Hydrogen bonds can form with

Answer 49

Oxygen nitrogen fluorine

Question 50

Percentage error

Answer 50

Error/amount x100

Question 51

Dipole

Answer 51

A difference in charge between two atoms caused by shift in electron density in the bond

Question 52

Entropy units

Answer 52

J/K/mol

Question 53

Standard entropy

Answer 53

The entropy of one mole of a substance understand his condition always positive

Question 54

Catalyst for breakdown of hydrogen peroxide

Answer 54

Magnesium oxide MNO2

Question 55

entropy

Answer 55

A term used for the dispersal of energy within the chemicals making up the chemical system

Question 56

Free energy change Delta G

Answer 56

The overall change in energy during a chemical reaction

Question 57

Enthalpy

Answer 57

The measure of the heat energy in a chemical system

Question 58

Ethanolic acid

Answer 58

CH3COOH