Definitions

Question 1

Define relative atomic mass

Answer 1

the weighted mean mass of an atom of an element relative to 1/12 of the mass of an atom of 12C

Question 2

Define relative isotopic mass

Answer 2

the mass of an atom of an isotope compared to 1/12 the mass of an atom of 12C

Question 3

Define 1st ionisation energy

Answer 3

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

Question 4

Define nuclear attraction

Answer 4

the attractive force that the outer shell of electrons experiences from the nucleus

Question 5

Define shielding

Answer 5

the repulsion between electrons in inner shells

Question 6

Define an orbital

Answer 6

a region within an atom that can hold up to 2 electrons with opposite spin

Question 7

Define a subshell

Answer 7

a group of the same type of atomic orbitals within a shell

Question 8

Define electronegativity

Answer 8

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

Question 9

Define a hydrogen bond

Answer 9

the attraction between the d+ H atom on 1 molecule and the lone pair of electrons on the d- Fluorine, Nitrogen or Oxygen on a different molecule

Question 10

What is the equation for finding the number of particles in a substance?

Answer 10

number of particles = ( mass (g) / molar mass (g/mol) ) x 6.02x10^23
(number of particles = moles x 6.02x10^23)

Question 11

What is the equation for atom economy?

Answer 11

atom economy = ( sum of molar masses of desired products / sum of molar masses of all products ) x 100

Question 12

What is the equation for percentage yield?

Answer 12

percentage yield = (actual yield / theoretical yield ) x100

Question 13

What is the ideal gas equation? What are the units?

Answer 13

pV = nRT

pressure(Pa) x volume(m^3) = number of moles x gas constant x temperature(K)

Question 14

What is the gas constant?

Answer 14

8.314 J/mol/K

Question 15

How do you convert celsius to kelvin?

Answer 15

add 273 degrees

Question 16

What is Avagadro’s constant?

Answer 16

6.02 x10^23

Question 17

Define molecular formula

Answer 17

the exact number of atoms of each element present in a molecule

Question 18

Define empirical formula

Answer 18

the simplest whole number ratio of atoms in a molecule

Question 19

Define homologous series

Answer 19

a series of compounds with the same functional group, with each successive member differing by a CH2 group, and having the same general formula

Question 20

Define homolytic fission

Answer 20

when a covalent bond breaks and one electron from the bonding pair is given to each atom previously involved in the bond to create 2 free radicals

Question 21

Define a radical

Answer 21

an atom with a single unpaired electron that is very reactive

Question 22

Define heterolytic fission

Answer 22

when a covalent bond breaks and one atom takes both of the bonding pair of electrons to become a negative ion, leaving the other atom as a positive ion

Question 23

Define a sigma bond

Answer 23

the overlapping of 2 orbitals directly in the plane of the 2 atoms

Question 24

Define hydrolysis

Answer 24

using water to break chemical bonds

opposite of condensation

Question 25

Define standard enthalpy of combustion

Answer 25

the enthalpy change when 1 mole of a substance is completely combusted with oxygen under standard conditions with all products and reactants in their standard states

Question 26

Define standard enthalpy of neutralisation

Answer 26

the enthalpy change when 1 mole of water is produced by the reaction of an acid and a base, under standard conditions

Question 27

Define standard enthalpy of formation

Answer 27

the enthalpy change when 1 mole of a substance is formed from its elements under standard conditions

Question 28

Define standard enthalpy of atomisation

Answer 28

the enthalpy change when 1 mole of gaseous atoms of a substance are formed from the substance in its standard state, under standard conditions

Question 29

What are standard conditions?

Answer 29

298 degrees K and 100kPa

Question 30

Define enthalpy change of reaction

Answer 30

the enthalpy change accompanying a reaction in the molar quantities shown under standard conditions, with reactants and products in their standard states

Question 31

Define first electron affinity

Answer 31

the enthalpy change when each atom in one mole of gaseous atoms gains one electron to form one mole of gaseous 1- ions

Question 32

Define second electron affinity

Answer 32

enthalpy change when each ion in one mole of gaseous 1- ions gains one electron to form one mole of gaseous 2- ions.

Question 33

Define hydration enthalpy

Answer 33

enthalpy change when one mole of gaseous ions becomes hydrated (dissolved in water) (g) => (aq)

Question 34

Define enthalpy of solution

Answer 34

the enthalpy change when one mole of an ionic solid is dissolved in an amount of water large enough so that the dissolved ions are well separated and do not interact with each other

Question 35

Define bond dissociation enthalpy

Answer 35

the enthalpy change when one mole of covalent bonds is broken in the gaseous state

Question 36

Define lattice enthalpy of formation

Answer 36

the enthalpy change when one mole of a solid ionic compound is formed from its constituent ions in the gas phase (g) => (s)

Question 37

Define lattice enthalpy of dissociation

Answer 37

the enthalpy change when one mole of a solid ionic compound is broken up into its constituent ions in the gas phase (s) => (g)

Question 38

Define enthalpy of vaporisation

Answer 38

enthalpy change when one mole of liquid is turned into a gas (l) => (g)

Question 39

Define enthalpy of fusion ?

Answer 39

the enthalpy change when one mole of a solid is turned into a liquid (s) => (l)

Question 40

Define enthalpy of neutralisation

Answer 40

the enthalpy change when 1 mole of water is formed in a reaction between an acid and an alkali under standard conditions

Question 41

Define standard electrode potential

Answer 41

the electromotive force of a half cell compared to the standard hydrogen electrode measured at 298K, solution conc. 1 moldm-3 and at a pressure of 100kPa

Question 42

Define a condensation polymer

Answer 42

a long chain molecule formed by the joining together of monomers with the loss of a small molecule (H2O or HCl)