2.1

Question 1

Relative atomic mass

Answer 1

The weighted average mass of an atom of an element compared to 1/12 the mass of carbon 12

Question 2

Ar=

Answer 2

((Isotope mass)x(percentage))+(isotope mass x%)/100

Question 3

Number of particles is

Answer 3

Moles x avogadros constant

Question 4

the Greek atom

Answer 4

Democritus said that the division of matter must have a lower limit eventually you would end up with an indivisible particle an atom

Question 5

Dalton’s atomic theory

Answer 5

atoms are particles that make up elements, atoms cant be divided, all atoms of an element are the same, atoms of one element are different to atoms of another element

Question 6

jj Thompson and electrons

Answer 6

discovered that cathode rays were a stream of particles(electrons) that were: negatively charged, can be deflected by magnets and electric fields, very small mass

Question 7

plum pudding model

Answer 7

electrons float in a sea of positive charge - proposed by jj Thompson

Question 8

Ernest Rutherford’s gold leaf experiment

Answer 8

alpha particles were directed at a gold sheet, most not deflected, some deflected through large angles and few reflected. shows that most of an atom is empty space, positive charge in the middle with most of the mass, overall charges balance

Question 9

Neil Bohr’s model

Answer 9

altered Rutherfords model so electrons only follow certain paths otherwise they would spiral into the nucleus. explained emission and absorption spectra and the energy of electrons at different distances from the nucleus

Question 10

what did Rutherford’s discovery of the proton explain

Answer 10

explain the link between atomic number and x-ray frequencies

Question 11

what are isotopes

Answer 11

when atoms of the same element have a different number of neutrons

Question 12

why do isotopes of the same element have the same properties

Answer 12

chemical properties are linked to the number of electrons which is linked to the number of protons not neutrons

Question 13

nitrate ion

Answer 13

NO3 -

Question 14

carbonate ion

Answer 14

CO3 2-

Question 15

sulfate ion

Answer 15

SO4 2-

Question 16

hydroxide ion

Answer 16

OH-

Question 17

ammonium ion

Answer 17

NH4+

Question 18

zinc ion

Answer 18

Zn 2+

Question 19

silver ion

Answer 19

Ag+

Question 20

how to find the number of moles in a sample

Answer 20

moles=mass/molar mass

Question 21

empirical formula

Answer 21

the simplest whole number ratio of atoms in a molecule

Question 22

molecular formula

Answer 22

shows the number of atoms in a molecule

Question 23

how to work out concentration

Answer 23

moles= concentration x volume

Question 24

ideal gas equation

Answer 24

pv=nrt

Question 25

simplified ideal gas equation

Answer 25

n=v/24

Question 26

percentage yield=

Answer 26

(actual yield/theoretical yield)x100

Question 27

reasons for low percentage yield

Answer 27

side reactions may occur, reaction may be at equilibrium, reactants may not be pure, some reactants may be left in apparatus

Question 28

how to calculate atom economy

Answer 28

(mr of desired product/ mr of all products)x 100

Question 29

water of crysalisation

Answer 29

when ionic compounds form there are often moles of water trapped in them shown as part of the formula after a dot

Question 30

hydrated compounds

Answer 30

compounds containing water in their crystalline form

Question 31

anhydrous compounds

Answer 31

no water in their crystalline form

Question 32

oxidation

Answer 32

loss of electrons, oxidation state increases

Question 33

reduction

Answer 33

gaining electrons, oxidation state is reduced

Question 34

rules for assigning oxidation states

Answer 34

elements=0, 1,2,3, F=-1, H=+1,O=-2, Cl=-1

Question 35

What is a base

Answer 35

A proton acceptor

Question 36

What is an alkali

Answer 36

Compound that looses oh ions in solution

Question 37

What is a salt

Answer 37

Chemical compound formed when an h+ ion in an acid is replaced by a metal ion or nh4 + ion