definitions?

Question 1

empirical formula

Answer 1

ratio of atoms or ions in a structure

Question 2

molar gas volume

Answer 2

volume per mole of gas molecule

at its stated temperature and pressure

Question 3

1 mol of gas molecules (at RTP) =

Answer 3

24 dm^3

Question 4

ideal gas constant (R)

Answer 4

8.314 J mol^-1 K^-1

Question 5

0 degrees celsius = kelvin

Answer 5

273

Question 6

RTP

Answer 6

20 degrees celsius

101 kPa (1atm)

Question 7

strong acid

Answer 7

acid that completely dissociates in aqueous solutions

Question 8

weak acid

Answer 8

acid that partially dissociates in aqueous solutions

Question 9

base

Answer 9

proton acceptor

Question 10

bond enthalpy

Answer 10

enpalthy change when 1 mol of gaseous covalent bonds are broken

Question 11

average bond enthalpy

Answer 11

the average bond break enthalpy for a particular bond in a range of different compounds

Question 12

how many electrons in any orbital

Answer 12

2

Question 13

s-orbital

Answer 13

sphere shape

greater the shell number, the greater the radius

Question 14

p-orbital

Answer 14

dumbbell shape

has three separate p-orbitals at right angles of another

higher the shell number n, higher the distance p-orbital is from nucleus

Question 15

alkali

Answer 15

base that dissolves in water releasing OH- ions

Question 16

ionic bond

Answer 16

electrostatic attraction between positive and negative ions

these are held in ionic compounds

Question 17

covalent bondING

Answer 17

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

Question 18

covalent bond

Answer 18

the overlap of atomic orbitals, each containing an electron to give a shared pair of electrons

shared pair of electron is attracted to nuclei of both bonded atoms

covalent attraction is localised - acts solely between shared pair of electrons and nuclei of bonded atoms (forming a molecule)

Question 19

dative (coordinate) bond

Answer 19

covalent bond where shared pair of electrons has been supplied by only one of the bonding atoms

Question 20

electron pair repulsion theory

Answer 20

electrons have negative charge, so electron pairs repel one another

Question 21

relative isotopic mass

Answer 21

mass of an isotope relative to 1/12th of the mass of an atom of carbon-12

Question 22

relative atomic mass

Answer 22

weighted mean mass of an atom of an element relative to 1/12th of the mass of an aatom of carbon-12

Question 23

binary compound

Answer 23

contains two elements only

Question 24

formula unit

Answer 24

formula worked out from the ionic charges that is used in equations

Question 25

molar mass

Answer 25

mass per mole of a substance

g mol^-1

Question 26

relative molecular mass (Mr)

Answer 26

compares mass of a molecule with the mass of carbon-12

Question 27

relative formula mass

Answer 27

compares mass of a 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 28

standard solution

Answer 28

solution of known concentration

Question 29

limiting reactant

Answer 29

the reactant not in excess that is completely used up first and stops the reaction