year 1 definitions

Question 1

what is an isotope

Answer 1

an atom of the same element with different numbers of neutrons and different masses

Question 2

what is relative isotopic mass

Answer 2

mass compared with 1/12th mass of carbon-12

Question 3

what is relative atomic mass

Answer 3

weighted mean mass compared with 1/12th mass of carbon-12

Question 4

what is molar mass

Answer 4

mass per mole (g/mol)

Question 5

what is molar gas volume

Answer 5

gas volume per mole (dm3/mol

Question 6

what is the empirical formula

Answer 6

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

Question 7

what is molecular formula

Answer 7

number and type of atoms of each element in a molecule

Question 8

what are the units for concentration

Answer 8

mol/dm3 and g/dm3

Question 9

what is the ideal gas equation

Answer 9

pV=nRT

Question 10

what is the percentage yield of a reaction

Answer 10

actual yield/theoretical yield x 100

Question 11

what is the atom economy of a reaction

Answer 11

Mr of desired product/Mr of total products x 100

Question 12

what are the benefits for sustainability of reactions with high atom economy

Answer 12

less waste products are produced and they make the best use of natural resources

Question 13

what is an acid

Answer 13

a substance that releases H+ ions in aq solution

Question 14

what is an alkali

Answer 14

a substance that releases OH- ions in aq solution

Question 15

what is a weak acid

Answer 15

an acid that partially dissociates in aqueous solution

Question 16

what is a strong acid

Answer 16

an acid that completely dissociates in aq solution

Question 17

what does the reaction between an acid and a base form

Answer 17

salts

Question 18

what does an acid and a metal form

Answer 18

salt and hydrogen

Question 19

what is an atomic orbital

Answer 19

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

Question 20

what is ionic bonding

Answer 20

electrostatic attraction between positive and negative ions

Question 21

what is a covalent bond

Answer 21

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

Question 22

what is a dative covalent bond

Answer 22

a shared pair of electrons in which both electrons come from the same atom

Question 23

what is average bond enthalpy

Answer 23

a measurement of covalent bond strength

Question 24

what is electronegativity

Answer 24

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

Question 25

what is a permanent dipole

Answer 25

weak intermolecular forces of attraction that arise between permanently polar molecules

Question 26

what is a polar bond

Answer 26

a bond formed when a shared pair of electrons are not shared equally

Question 27

what is hydrogen bonding

Answer 27

intermolecular bonding between molecules containing N, O, or F and the H atom of -NH, -OH, or HF

Question 28

explain the solid structures of simple molecular lattices

Answer 28

covalently bonded molecules attracted by intermolecular forces

Question 29

what are the 3 ways the periodic table is organised

Answer 29

- increasing atomic number - in periods showing repeating trends in physical and chemical properties - in groups with similar chemical properties

Question 30

what is 1st ionisation energy

Answer 30

removal of 1 mol of electrons from 1 mol of gaseous atoms

Question 31

what is metallic bonding

Answer 31

strong electrostatic attraction between cations and delocalised electrons

Question 32

what is a giant metallic lattice structure

Answer 32

positive ions arranged in regular layers, with delocalised electrons free to move throughout the structure

Question 33

what can calcium hydroxide be used for

Answer 33

to neutralise acidic soils in agriculture

Question 34

what can Mg(OH)2 and CaCO3 be used for

Answer 34

antacids to treat indigestion

Question 35

what is disproportionation

Answer 35

oxidation and reduction of the same element in a reaction

Question 36

what are the benefits of using chlorine to treat water

Answer 36

killing bacteria

Question 37

what are the risks of using chlorine to treat water

Answer 37

- chlorine is a respiratory irritant - can react with organic hydrocarbons such as methane to form chlorinated hydrocarbons which are thought to cause cancer

Question 38

what is the activation energy

Answer 38

minimum energy required for a reaction to take place

Question 39

what is the enthalpy change of reaction

Answer 39

enthalpy change associated with a stated equation

Question 40

what is the enthalpy change of formation

Answer 40

formation of 1 mol of a compound from its elements

Question 41

what is the enthalpy change of combustion

Answer 41

complete combustion of 1 mol of a substance

Question 42

what is the enthalpy change of neutralisation

Answer 42

formation of 1 mol of water from neutralisation