harder questions

Question 1

give two reasons why the electrolysis is carried out on aluminium oxide dissolved in molten cryolite instead of electrolysing molten aluminium oxide only

Answer 1

imrpoves conductivity of the electrolyte
lower operating temp

Question 2

what is meant by term amphoteric

Answer 2

neutralises both acids and bases

Question 3

what is the substance that reacts with oleum to form sulfuric acid

Answer 3

water

Question 4

Name the black solid that is produced when concentrated sulfuric acid is added to sugar,
C12H22O11.

Answer 4

carbon

Question 5

Name the type of reaction in which proteins are broken down into amino acids

Answer 5

hydrolysis

Question 6

Name two types of substance that are used to break down proteins into amino acids

Answer 6

enzymes and acids

Question 7

Name the process used to separate the amino acids

Answer 7

chromotogrpahy

Question 8

Name the type of substance used to detect the amino acids.

Answer 8

locating agent

Question 9

Give the symbol of the value used to determine the identity of each amino acid after separation and detection

Answer 9

rf value

Question 10

Name a synthetic polyamide.

Answer 10

nylon

Question 11

Identify the two functional groups present in the monomers used to produce synthetic
polyamides.

Answer 11

carboxylic acid
amine

Question 12

what isthe color of copper in electrolysis

Answer 12

pink/brown

Question 13

why are carbon electrodes used

Answer 13

inert, conducts electricity

Question 14

why is the universal indicator not fit for use in titration

Answer 14

too many colour changes

Question 15

what happens when hydrogen peroxide reacts with manganese oxide catalyst

Answer 15

oxygen is produced

Question 16

State what happens to the colour of the aqueous copper(II) sulfate as this electrolysis progresses.

Answer 16

becomes colourless solution

Question 17

State one disadvantage, other than cost, of using hydrogen–oxygen fuel cells to power
cars compared to using petrol.

Answer 17

needs high pressure to store hydrogen

Question 18

Name the substance used to remove sulfur dioxide in flue gas desulfurisation.

Answer 18

calcium oxide

Question 19

State one use of ammonium sulfate.

Answer 19

fertiliser

Question 20

general formula for carboxylic acids is

Answer 20

CnH2n+1COOH

Question 21

how many water molecules are binded to hydrated copper sulfate

Answer 21

5
CuSO4 . 5H2O

Question 22

how many water molecules are binded to hydrated cobalt chloride

Answer 22

6
CoCL2 . 6H2O

Question 23

State the meaning of the Roman numeral after a compound

Answer 23

oxidation state

Question 24

what is a suitable catalyst for the formation of an ester

Answer 24

acid

Question 25

what element is stored under oil

Answer 25

potassium and sodium

Question 26

what is found in the ore of zinc blende

Answer 26

sinc and sulfur

Question 27

what happens when sucrose is dehydrated by concentrated sulfuric acid what is formed

Answer 27

carbon

Question 28

test for chlorine and result

Answer 28

damp litmus paper turn s blue

Question 29

explain why iron doesn't rust even if zinc is scratched

Answer 29

zinc is more reactive than iron zinc loses electrons / zinc is oxidised electrons are transferred to iron / iron is not oxidised / iron does not lose electrons

Question 30

what is the colour of nitrogen oxide

Answer 30

brown gas

Question 31

type of particle responsible for the conduction of electricity during electrolysis in electrolyte

Answer 31

ions

Question 32

which substance is used to bleach wood pulp

Answer 32

sulfur dioxide

Question 33

what is used as a fuel in fuel cells

Answer 33

hydrogen

Question 34

what catalyst is used in a catalytics converter

Answer 34

platinum

Question 35

how can Complex carbohydrates break down to form simple sugars.

Answer 35

acids enzymes

Question 36

how do you form a polymer from a unit of glucose (OH)

Answer 36

remove the h, and only have O links

Question 37

When aqueous ammonia is added to aqueous iron(II) sulfate a green precipitate is seen, name precipitate

Answer 37

iron (ii) hydroxide

Question 38

suggest why the green ppt turns red near surface standing

Answer 38

iron (ii) hydroxide is oxidised by its reaction with air to form iron(iii) hydroxide

Question 39

suggest all particles responsible for the passage of electricity in molten copper(II) bromide

Answer 39

cuˆ2+ brˆ-

Question 40

Suggest the name of a metal which could be used as the inert electrodes.

Answer 40

platinum

Question 41

Suggest the change, if any, in the voltmeter reading if the zinc electrode was replaced with an iron electrode. Explain your answer.

Answer 41

voltage decreases because zinc is more reactive than iron

Question 42

The zinc electrode was replaced with a silver electrode. The reading on the voltmeter was –0.46 V. Suggest why the sign of the voltmeter reading became negative

Answer 42

silver is less reactive than copper

Question 43

in an electrolysis of concentrated sulphuric acid, electrodes one is made of copper and the other of zinc, what is the electron flow

Answer 43

from zinc to copper, because zinc is more reactive, more easily loses electrons

Question 44

what is an element

Answer 44

made of atoms with same atomic number cant be broken down into simpler substances

Question 45

How would you show that an aqueous solution of ethanoic acid is an acid without using an indicator or measuring the pH?

Answer 45

react it with a metal eg. magnesium, would see effervesces and metal dissolving

Question 46

metal oxides are acidic or basic give examples

Answer 46

basic cuO and CaO

Question 47

non metal oxides are acidic or basic give examples

Answer 47

acidic eg. CO2 and SO2

Question 48

amphoteric acids meaning and give examples

Answer 48

neutralise both acids and bases ZnO and Al2O3

Question 49

what salts are soluble

Answer 49

all sodium potassium ammonium and all nitrates all chlorides except silver and lead al iodine and bromide accept silver all sulfates except, lead, calcium and barium

Question 50

what salts are insoluble

Answer 50

all carbonates except- sodium potassium ammonium all hydroxides except- sodium potassium ammonium silver chloride, lead chloride, silver bromide, silver iodide, barium sulfate, calcium sulfate, lead sulfate

Question 51

what is the order of the fractional distillation of petroleum

Answer 51

refinery gas petrol naptha kerosene diesel oil lubricating oil fuel oil bitumen

Question 52

conditions needed in a catalytic converter

Answer 52

high temperature and platinum catalyst

Question 53

conditions needed in cracking

Answer 53

ceramic catalyst and high temp

Question 54

conditions needed in esterification

Answer 54

acid (inorganic) catalyst

Question 55

what are the golden five

Answer 55

nitrate- NO3 - carbonate- CO3 2- hydroxide- OH- sulphate- SO4 2- ammonium- NH4 +

Question 56

ammonia gas formula

Answer 56

NH3

Question 57

how is sulfuric acid formed from sulfur trioxide

Answer 57

sukfur trioxide reacts with sulfuric acid froming oleum oleum reacts with water to form sulfuric acid

Question 58

how does burning sulfur ores cause acid rain

Answer 58

produces sulfur dioxide, which reacts with water from rain

Question 59

what is PET also known as

Answer 59

terylene

Question 60

how do you find percentage yield

Answer 60

find number of moles of each compound, (remember to remove ratio) and then divide the reactant by the product moles and times by 100%

Question 61

what are the trends of the group 2

Answer 61

alkali metals- soft metals, low densities and low melting points going down group: increase density increase reactivity decrease melting point

Question 62

what are the trends of group 7

Answer 62

halogens- diatomic atoms going down group: increase density increase melting point decrease reactivity

Question 63

charge of silver

Answer 63

+1

Question 64

how do you convert an alkene to an alkane

Answer 64

you add hydrogen

Question 65

what reagents are needed to convert an alkene to ethanol (as the only product)

Answer 65

steam

Question 66

whats the type of reaction that occurs when an alkene is converted to ethanol as the only product

Answer 66

addition

Question 67

Explain, in terms of attractive forces between particles, why LiCl is a solid at room temperature but NCl 3 is a liquid with a relatively low boiling point.

Answer 67

licl has ionic bonds attraction between molecules in NCl3 have weak attraction (weak intermolecular forces) take more energy to break strong ionic bonds

Question 68

what does fluorine look in room temp

Answer 68

yellow pale gas

Question 69

Describe how you would make a sample of limewater starting with solid calcium hydroxide

Answer 69

add excess calcium hydroxide to water, then filter

Question 70

Some sulfur is obtained by mining. Name one other major source of sulfur

Answer 70

fossil fuels or petroleum

Question 71

State and explain the effect of increasing the pressure on the rate of the forward reaction

Answer 71

more particles per unit volume rate increases more collisions per sec

Question 72

what happens when a highly reactive metal nitrate thermally decomposes

Answer 72

(potassium sodium and calcium) metal nitrate + oxygen 2metalNO3(s) -> 2metalNO2(s) + O2(g)

Question 73

what happens when a mild reactive metal nitrate thermally decomposes

Answer 73

( magnesium, aluminum, zinc, iron, copper) metal oxide + nitrogen dioxide + oxygen 2metal(nitrate) -> metalO(s)+ NO2(g) +O2(g)

Question 74

what happens when a weak reactive metal nitrate thermally decomposes

Answer 74

(silver and gold) metal + nitrogen dioxide + oxygen metal nirate(s)-> metal(s) NO2(g) + O2(g)

Question 75

what is the rule for metal carbonates and thermal decompositon? and what are the products

Answer 75

only mildly reactive metals react with heat forms: metal oxide + carbon dioxide

Question 76

what is the rule for metal oxides and thermal decompositon? and what are the products

Answer 76

only low reactive metals react with heat to form: metal + oxygen

Question 77

what is the colour of solution during electrolysis of copper sulfate using carbon electrodes

Answer 77

solution colour fades because copper ions are removed and not replaced

Question 78

what is the colour of solution during electrolysis of copper sulfate using copper electrodes

Answer 78

colour remains the same because copper ions are removed but alos replaced

Question 79

which element is used as a food preservative

Answer 79

sulfur dioxide

Question 80

what happens when weak metal carbonates thermal decompose

Answer 80

forms metal +carbon dioxide + oxygen

Question 81

Explain why the rate of reaction is highest at the start of the reaction.

Answer 81

collision frequency is highest at the start, bigger concentration of reactants at the start of the reaction

Question 82

Explain, in terms of bonding, why sodium oxide has a high melting point.

Answer 82

positive ions and negative ions strong attraction / strong bonds

Question 83

State one advantage of using hydrogen–oxygen fuel cells instead of petrol in vehicle engines.

Answer 83

no co2 involved more efficient