unit 2 definitions

Question 1

define the mole (2)

Answer 1

• The amount of substance that has the same number of particles
• as there are atoms in 12g of 12C

Question 2

define amount of a substance (2)

Answer 2

• The number of particles
• equivalent to the relative atomic, molecular, or formula mass of a substance

Question 3

define molecular formula

Answer 3

The actual number of atoms of each element in a molecule

Question 4

define empirical formula (2)

Answer 4

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

Question 5

define hydrated crystal

Answer 5

crystalline compound that contains water

Question 6

define anhydrous crystal

Answer 6

crystalline compound containing no water

Question 7

Define isotope (2)

Answer 7

• atoms of the same element
• with diff number of neutrons

Question 8

Define relative isotopic mass (2)

Answer 8

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

Question 9

Define relative atomic mass (2)

Answer 9

• weighted mean mass of an atom
• relative to 1/12th the mass of a carbon 12 atom

Question 10

Define relative molecular mass (2)

Answer 10

• weighted mean mass of a molecule
• relative to 1/12th the mass of an atom of carbon 12

Question 11

Define relative formula mass of (2)

Answer 11

• weighted mean mass of one formula unit
• relative to 1/12th the mass of a carbon 12 atom

Question 12

Define the term acids (1)

Answer 12

Release H+ ions in solution

Question 13

Define the term alkalis (1)

Answer 13

Release OH- ions in solution

Question 14

Define the term amphoteric (1)

Answer 14

• can act as an acid or a base

Question 15

Define the term string acids (1)

Answer 15

Strong acids will fully dissociate in solution

Question 16

Define the term weak acids (1)

Answer 16

Weak acids will partially dissociate in solution

Question 17

Define the term neutralisation reaction (1)

Answer 17

Acid and base react together to form a salt and water

Question 18

Define the term standard solution (1)

Answer 18

A Solution of known concentration

Question 19

Define the term disproportination (1)

Answer 19

Oxidation and reduction if same element in a reaction

Question 20

Define oxidising agent (2)

Answer 20

• a species which oxidises another species
• the species itself in reduced

Question 21

Define the term reducing agent (2)

Answer 21

• species which reduces another agent
• Species itself is oxidised

Question 22

define ionic bonding (2)

Answer 22

• electrostatic attraction
• between + and - ions

Question 23

define electrostatic attraction (3)

Answer 23

• 2 ptcls
• w opp charge
• that attract

Question 24

what is meant by a bond ? (1)

Answer 24

a region of electron density

Question 25

define covalent bonding (3)

Answer 25

- strong electrostatic attraction - between a shared pair of e- - and nuclei of bonded atoms

Question 26

define electronegativity (3)

Answer 26

- ability of an atom - to attract a pair of electrons towards itself - in a cov bond

Question 27

define polar mlcl (3)

Answer 27

- mlcl that conatins polar bonds - with dipoles - that dont cancel out due to their direction

Question 28

define IDDI (4)

Answer 28

- intermlclr forces - caused by random mvmnt of e- - creating a temporary dipole - that induces a dipole in neigboring mlcl

Question 29

define PDDI (2)

Answer 29

- weak intermolecular FOA - between polar mlcls

Question 30

define hydrogen bonding (3)

Answer 30

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