harder questions Flashcards
give two reasons why the electrolysis is carried out on aluminium oxide dissolved in molten cryolite instead of electrolysing molten aluminium oxide only
imrpoves conductivity of the electrolyte
lower operating temp
what is meant by term amphoteric
neutralises both acids and bases
what is the substance that reacts with oleum to form sulfuric acid
water
Name the black solid that is produced when concentrated sulfuric acid is added to sugar,
C12H22O11.
carbon
Name the type of reaction in which proteins are broken down into amino acids
hydrolysis
Name two types of substance that are used to break down proteins into amino acids
enzymes and acids
Name the process used to separate the amino acids
chromotogrpahy
Name the type of substance used to detect the amino acids.
locating agent
Give the symbol of the value used to determine the identity of each amino acid after separation and detection
rf value
Name a synthetic polyamide.
nylon
Identify the two functional groups present in the monomers used to produce synthetic
polyamides.
carboxylic acid
amine
what isthe color of copper in electrolysis
pink/brown
why are carbon electrodes used
inert, conducts electricity
why is the universal indicator not fit for use in titration
too many colour changes
what happens when hydrogen peroxide reacts with manganese oxide catalyst
oxygen is produced
State what happens to the colour of the aqueous copper(II) sulfate as this electrolysis progresses.
becomes colourless solution
State one disadvantage, other than cost, of using hydrogen–oxygen fuel cells to power
cars compared to using petrol.
needs high pressure to store hydrogen
Name the substance used to remove sulfur dioxide in flue gas desulfurisation.
calcium oxide
State one use of ammonium sulfate.
fertiliser
general formula for carboxylic acids is
CnH2n+1COOH
how many water molecules are binded to hydrated copper sulfate
5
CuSO4 . 5H2O
how many water molecules are binded to hydrated cobalt chloride
6
CoCL2 . 6H2O
State the meaning of the Roman numeral after a compound
oxidation state
what is a suitable catalyst for the formation of an ester
acid
what element is stored under oil
potassium and sodium
what is found in the ore of zinc blende
sinc and sulfur
what happens when sucrose is dehydrated by concentrated sulfuric acid what is formed
carbon
test for chlorine and result
damp litmus paper turn s blue
explain why iron doesn’t rust even if zinc is scratched
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
what is the colour of nitrogen oxide
brown gas
type of particle responsible for the conduction of electricity during electrolysis in electrolyte
ions
which substance is used to bleach wood pulp
sulfur dioxide
what is used as a fuel in fuel cells
hydrogen
what catalyst is used in a catalytics converter
platinum
how can Complex carbohydrates break down to form simple sugars.
acids
enzymes
how do you form a polymer from a unit of glucose (OH)
remove the h, and only have O links
When aqueous ammonia is added to aqueous iron(II) sulfate a green precipitate is seen, name precipitate
iron (ii) hydroxide
suggest why the green ppt turns red near surface standing
iron (ii) hydroxide is oxidised by its reaction with air to form iron(iii) hydroxide
suggest all particles responsible for the passage of electricity in molten copper(II) bromide
cuˆ2+
brˆ-
Suggest the name of a metal which could be used as the inert electrodes.
platinum
Suggest the change, if any, in the voltmeter reading if the zinc electrode was replaced with an iron electrode. Explain your answer.
voltage decreases because zinc is more reactive than iron
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
silver is less reactive than copper
in an electrolysis of concentrated sulphuric acid, electrodes one is made of copper and the other of zinc, what is the electron flow
from zinc to copper, because zinc is more reactive, more easily loses electrons
what is an element
made of atoms with same atomic number
cant be broken down into simpler substances
How would you show that an aqueous solution of ethanoic acid is an acid without using an indicator or measuring the pH?
react it with a metal eg. magnesium, would see effervesces and metal dissolving
metal oxides are acidic or basic give examples
basic
cuO and CaO
non metal oxides are acidic or basic give examples
acidic eg. CO2 and SO2
amphoteric acids meaning and give examples
neutralise both acids and bases
ZnO and Al2O3
what salts are soluble
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
what salts are insoluble
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
what is the order of the fractional distillation of petroleum
refinery gas
petrol
naptha
kerosene
diesel oil
lubricating oil
fuel oil
bitumen
conditions needed in a catalytic converter
high temperature and platinum catalyst
conditions needed in cracking
ceramic catalyst and high temp
conditions needed in esterification
acid (inorganic) catalyst
what are the golden five
nitrate- NO3 -
carbonate- CO3 2-
hydroxide- OH-
sulphate- SO4 2-
ammonium- NH4 +
ammonia gas formula
NH3
how is sulfuric acid formed from sulfur trioxide
sukfur trioxide reacts with sulfuric acid froming oleum
oleum reacts with water to form sulfuric acid
how does burning sulfur ores cause acid rain
produces sulfur dioxide, which reacts with water from rain
what is PET also known as
terylene
how do you find percentage yield
find number of moles of each compound, (remember to remove ratio) and then divide the reactant by the product moles and times by 100%
what are the trends of the group 2
alkali metals- soft metals, low densities and low melting points
going down group:
increase density
increase reactivity
decrease melting point
what are the trends of group 7
halogens- diatomic atoms
going down group:
increase density
increase melting point
decrease reactivity
charge of silver
+1
how do you convert an alkene to an alkane
you add hydrogen
what reagents are needed to convert an alkene to ethanol (as the only product)
steam
whats the type of reaction that occurs when an alkene is converted to ethanol as the only product
addition
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.
licl has ionic bonds
attraction between molecules in NCl3 have weak attraction (weak intermolecular forces)
take more energy to break strong ionic bonds
what does fluorine look in room temp
yellow pale gas
Describe how you would make a sample of limewater starting with solid calcium hydroxide
add excess calcium hydroxide to water, then filter
Some sulfur is obtained by mining.
Name one other major source of sulfur
fossil fuels or petroleum
State and explain the effect of increasing the pressure on the rate of the forward reaction
more particles per unit volume
rate increases
more collisions per sec
what happens when a highly reactive metal nitrate thermally decomposes
(potassium sodium and calcium)
metal nitrate + oxygen
2metalNO3(s) -> 2metalNO2(s) + O2(g)
what happens when a mild reactive metal nitrate thermally decomposes
( magnesium, aluminum, zinc, iron, copper)
metal oxide + nitrogen dioxide + oxygen
2metal(nitrate) -> metalO(s)+ NO2(g) +O2(g)
what happens when a weak reactive metal nitrate thermally decomposes
(silver and gold)
metal + nitrogen dioxide + oxygen
metal nirate(s)-> metal(s) NO2(g) + O2(g)
what is the rule for metal carbonates and thermal decompositon? and what are the products
only mildly reactive metals react with heat
forms:
metal oxide + carbon dioxide
what is the rule for metal oxides and thermal decompositon? and what are the products
only low reactive metals react with heat to form:
metal + oxygen
what is the colour of solution during electrolysis of copper sulfate using carbon electrodes
solution colour fades
because copper ions are removed and not replaced
what is the colour of solution during electrolysis of copper sulfate using copper electrodes
colour remains the same
because copper ions are removed but alos replaced
which element is used as a food preservative
sulfur dioxide
what happens when weak metal carbonates thermal decompose
forms metal +carbon dioxide + oxygen
Explain why the rate of reaction is highest at the start of the reaction.
collision frequency is highest at the start, bigger concentration of reactants at the start of the reaction
Explain, in terms of bonding, why sodium oxide has a high melting point.
positive ions and negative ions
strong attraction / strong bonds
State one advantage of using hydrogen–oxygen fuel cells instead of petrol in vehicle engines.
no co2 involved
more efficient
