periodic table and energy

Question 1

halide ions test

Answer 1

dissolve in nitric acid- prevent false pos from carbonate ions ppt out w Ag+
silver nitrate drowse
AgX ppt
cl white
br cream
I yellow
ammonia follow up test
cl dissolves in dilute
br in conc
I doesn’t

Question 2

carbonates test

Answer 2

aqueous hcl
gas produced tested in limewater Ca(OH)2
effervescence cos co2 produced

Question 3

sulfates test

Answer 3

acidify w dilute hcl
few drops of aqueous barium chloride
white ppt of BaSO4

Question 4

ammonium ions test

Answer 4

aqueous sodium hydroxide
ammonia gas produced
very soluble in water so no effervescence
pungent smell/ red litmus paper blue

Question 5

factors that affect ionisation energy

Answer 5

atomic radius
nuclear charge
electron shielding

Question 6

change in ionisation energy across a period

Answer 6

increases
increasing nuclear charge as more protons are added
no extra shielding (no extra shells)
decreasing atomic radius - atoms get smaller across a period as the same shell is pulled inwards by the extra protons

Question 7

change in ionisation energy down a group

Answer 7

decreases
nuclear charge increases
atomic radius increases
shielding increases
nuclear attraction decreases

Question 8

why is there a rapid decrease in ionisation energy between the last element in one period and the first in the next

Answer 8

increased atomic radius
increased shielding
these 2 factors outweigh increased atomic charge

Question 9

Cl2 colour in aqueous solution

Answer 9

pale green

Question 10

Br2 colour in aqueous solution

Answer 10

yellow

Question 11

I2 colour in aqueous solution

Answer 11

brown

Question 12

Cl2 colour in organic solution

Answer 12

colourless

Question 13

Br2 colour in organic solution

Answer 13

yellow

Question 14

I2 colour in organic solution

Answer 14

purple

Question 15

list the halogens in order of decreasing reactivity

Answer 15

Cl
Br
I

Question 16

what colour are halide salts

Answer 16

colourless

Question 17

why is organic solvent added after a displacement reaction between aqueous halide salt and aqueous halogen solution

Answer 17

to confirm a displacement reaction has taken place

Question 18

what type of reaction occurs between
aqueous halide salt
and
aqueous halogen solution

Answer 18

displacement

Question 19

group 2 reactivity trend down group

Answer 19

increases

Question 20

does Be react w water

Answer 20

no

Question 21

group 2 metal + water

Answer 21

group 2 hydroxide

Question 22

how does Mg react w water?

Answer 22

slowly w cold
vigorously w steam to produce MgO instead of Mg(OH)2

Question 23

group 2 metal + oxygen

Answer 23

group 2 oxide

Question 24

what are group 2 oxides

Answer 24

white solids

Question 25

group 2 oxide + water

Answer 25

group 2 hydroxide which dissociates to form OH-

Question 26

how does MgO react w water?

Answer 26

very slowly hydroxide barely dissolves

Question 27

pH trend of group 2 oxides down group

Answer 27

increases more alkaline because hydroxides become more soluble

Question 28

use of Ca(OH)2

Answer 28

neutralise acidic soils

Question 29

use of Mg(OH)2

Answer 29

neutralise excess stomach acid

Question 30

colour and state of fluorine

Answer 30

pale yellow gas

Question 31

colour and state of chlorine

Answer 31

pale green gas

Question 32

colour and state of bromine

Answer 32

brown- orange liquid

Question 33

colour and state of iodine

Answer 33

grey solid

Question 34

trend in electronegativity of halogens

Answer 34

decreases down group atoms get larger nuclear attraction decreases shielding increases

Question 35

Cl2 + 2NaOH

Answer 35

NaClO + NaCl + H2O NaClO is bleach/ sodium chlorate (1)

Question 36

metallic bonding definition

Answer 36

strong electrostatic attraction between cations (positive ions) and delocalised electrons

Question 37

disproportionation definition

Answer 37

oxidation and reduction of the same element

Question 38

benefits of chlorine use in water treatment

Answer 38

killing bacteria

Question 39

risks of chlorine use in water treatment

Answer 39

hazards of toxic chlorine gas and possible risks from formation of chlorinated hydrocarbons

Question 40

Activation energy definition

Answer 40

minimum energy required for a reaction to take place.

Question 41

enthalpy change of formation definition

Answer 41

formation of 1 mol of a compound from its elements

Question 42

enthalpy change of combustion definition

Answer 42

complete combustion of 1 mol of a substance

Question 43

enthalpy change of neutralisation definition

Answer 43

formation of 1 mol of water from neutralisation

Question 44

standard conditions

Answer 44

100kPa 298 K

Question 45

average bond enthalpy definition

Answer 45

breaking of 1 mol of bonds in gaseous molecules

Question 46

role of a catalyst

Answer 46

increasing reaction rate without being used up by the overall reaction allowing a reaction to proceed via a different route with lower activation energy

Question 47

how do catalysts have great economic importance and benefits for increased sustainability

Answer 47

by lowering temperatures and reducing energy demand from combustion of fossil fuels with resulting reduction in CO2 emissions

Question 48

dynamic equilibrium definition

Answer 48

exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction and the concentrations of reactants and products do not change

Question 49

do catalysts change the position of equilibrium

Answer 49

no increases the rate of both forward and reverse reactions in an equilibrium by the same amount

Question 50

what happens to the reactivity of the elements down group 2

Answer 50

increases

Question 51

what type of reaction occurs when group 2 metals react w water

Answer 51

redox

Question 52

how to find enthalpy change of reaction from enthalpy changes of formation

Answer 52

products - reactants

Question 53

when writing ionisation energy equations, what state symbol is used

Answer 53

gas

Question 54

fine detail for ammonium ions test

Answer 54

gentle heating