Exam Qs Flashcards
State why sewage and phosphates in river water is harmful (2)
sewage: contains microbes which cause disease (1)
phosphates: deoxygenation of water (1)
Describe how the general physical properties of a liquid differ from those of a solid.
Give two differences.
solid has a definite shape / solid has a fixed shape / liquid has no definite shape / liquid takes the shape of its container (1)
solid does not flow (over a surface easily) / liquid flows (easily over a surface) / solid does not spread out (over a
surface) / liquid spreads out (over a surface) (1)
State one source of the pollutant sulfur dioxide in the air other than from burning sulfur
combustion of fossil fuels (containing sulfur)
the chemical name of SiO2
Silicon (IV) oxide
State what is meant by the term covalent bond
pair of electrons shared between two atoms
Name a halide compound which can be used to detect the presence of water
Anhydrous cobalt (II) chloride
In the equation, methanoic acid is represented by the formula HCOOH.
Name this type of formula.
Structural
When but-1-ene reacts with steam, two possible products form. Identify the type of catalyst which is used in this reaction
Acid
State what is meant by the term closed system
nothing can enter or leave
Two possible products when but-1-ene reacts with steam
But-1-ol, but-2-ol
Name and describe the bonding in potassium (4)
metallic (1)
lattice of potassium ions (1)
sea of electrons (1)
attraction between potassium ions and electrons (1)
Temperature and pressure used in Haber process
450 degrees celsius
200 atm
Which element in period 2 has the highest rate of diffusion?
Neon
Which element in period 2 has the oxide responsible for acid rain?
Nitrogen
Explain, in terms of particles, what happens to the rate of reaction when the temperature is
reduced
M1 rate decreases and particles have less energy (1)
M2 less collisions (between particles) occur per second / per unit time (1)
M3 less of the particles/collisions have energy equal to or above the activation energy (1)
Two observations in the reaction of calcium chloride and nitric acid
- effervescence
- solid dissolves/disappears
Suggest what is meant by the term saturated solution
a solution that can contain no more solute at a given temperature
Write the chemical equation for the reaction when solid sodium nitrate is heated (decomposition)
2NaNO3 -> 2NaNO2 + O2
Bromine colour at room temp and bromine water colour
bromine by itself at room temp is red-brown but bromine water is orange
Describe the arrangement of atoms in graphite (2)
M1 layers
M2 hexagon(al) (rings of carbon)
Describe the process which converts metal ores to sulfur dioxide
strong heating in air / roasting in air
Suggest the name for a solution in which no more solute can dissolve
saturated
Suggest why more crystals of magnesium sulfate appear on cooling
solubility (of MgSO4 / solid) decreases (as temperature decreases)
Write the chemical equation for the reaction when solid magnesium nitrate is heated (2)
2Mg(NO3)2 → 2MgO + 4NO2 + O2
Give two reasons why the electrolysis is carried out on aluminium oxide dissolved in
molten cryolite instead of electrolysing molten aluminium oxide only
M1 improves conductivity of the electrolyte / makes the electrolyte a better conductor (1)
M2 lower operating temperature (1)
State what is meant by the term amphoteric
neutralises both acids AND alkalis
Name the black solid that is produced when concentrated sulfuric acid is added to sugar,
C12H22O11.
Carbon
Observations when solid copper(II) carbonate is added to aqueous potassium hydrogensulfate
- solid disappears
- blue solution
- bubbles / effervescence / fizzing
Name the type of reaction in which proteins are broken down into amino acids
Hydrolysis
State the percentage of nitrogen in clean, dry air
78%
Name the substance used to remove sulfur dioxide in flue gas desulfurisation
calcium oxide
Nitrogen dioxide, NO2, is formed in car engines.
Name the equipment in a car exhaust used to remove the NO2 formed in car engines
catalytic converter
State one adverse effect of carbon monoxide on human health
toxic
State what is meant by the symbol ∆H
enthalpy change
State one use of ammonium sulfate
fertiliser
Atm to kPa
1atm=100kPa
Some physical and chemical properties of transition elements are shown.
physical properties:
● high density
● high strength
chemical properties:
● form coloured compounds
● have ions with variable oxidation numbers
(i) State one other physical property of transition elements.
(ii) State one other chemical property of transition elements.
i) high melting point
ii) act as catalyst
State the meaning of the Roman numeral (II) in the name copper(II) oxide
the oxidation number of copper is +2
Propanoic acid forms an ester when it reacts with ethanol in the presence of a catalyst.
(i) Suggest a suitable catalyst
Acid or any named inorganic acid (phosphoric acid)
Which oxide is a reducing agent in the blast furnace?
Carbon monoxide
Why does group VII have the same chemical properties?
Because they have the same number of valence electrons
Describe two methods where sulfur dioxide is obtained
- Sulfur burned in air
- Roasting sulfide ores in air
Silicon tetrachloride has a low melting point because it has weak forces of attraction
between particles.
Name the type of particles that are held together by these weak forces of attraction
Molecules
Explain, in terms of structure and bonding, why silicon(IV) oxide has a high melting point
M1 covalent bonds
M2 strong bonds
and
giant (covalent) structure
Explain, in terms of collision theory, why the rate of reaction increases if powdered zinc is used rather than lumps
M1 greater surface area (of zinc)
M2 frequency of collisions between (zinc and acid) particles increases
State what is meant by the term electrolyte
M1 ionic compound
M2 molten and / or aqueous
The electrolysis of aqueous copper(II) sulfate is repeated using copper electrodes.
State what happens to the anode
Anode dissolves
State one disadvantage, other than cost, of using hydrogen–oxygen fuel cells to power
cars compared to using petro
needs high pressure to store hydrogen
The first stage is the conversion of ammonia into nitrogen monoxide, NO.
The equation is shown.
4NH3(g) + 5O2(g) 4NO(g) + 6H2O(g)
The reaction is carried out at a temperature of 900°C and a pressure of 7 atm.
The forward reaction is exothermic.
Using explanations that do not involve cost:
● explain why a temperature less than 900°C is not used
● explain why a pressure greater than 7 atm is not used
temperature change:
M1 low(er) rate (of reaction)
pressure change:
M2 (position of) equilibrium shifts to the left hand side/ towards reactants
A student makes aqueous copper(II) nitrate by adding an excess of solid copper(II) carbonate
to dilute nitric acid.
(ii) State two observations that indicate the copper(II) carbonate is in excess.
M1 undissolved solid
M2 effervescence stops on addition of more copper(II) carbonate
Name one compound, other than copper(II) carbonate, that can be added to dilute
nitric acid to produce aqueous copper(II) nitrate
Copper oxide
Copper hydroxide
addition polymer formed from but-2-ene
- Single bond between 2 carbon atoms
- 1 CH3 group and 1H on first carbon and same on second carbon
two reasons why coke is added to the blast furnace
- coke produces heat
- reducing agent to reduce iron (III) oxide
Explain how limestone removes impurities in the hematite
limestone thermally decomposes to form calcium oxide. Calcium oxide reacts with silicon (IV) oxide to produce slag
Write a symbol equation for the conversion of iron (III) oxide to iron in the blast furnace
Fe2O3 + 3CO -> 2Fe + 3CO2
Suggest why iron produced in the blast furnace is molten
Temperature in the furnace is higher than the melting point of iron
Explain why the structure of alloys causes them to be stronger and harder than pure metals
M1 atoms have different sizes (1)
M2 layers cannot slide over or past each other (1)
Substances that react with iron to form rust
oxygen and water
Explain how the coating of zinc prevents rusting if the zinc is not scratched
Zinc acts as a barrier which prevents oxygen and water reaching the iron
When zinc is scratched it is still protecting the iron, explain how
M1 zinc is more reactive than iron (1)
M2 zinc is oxidised / zinc loses electrons / zinc forms positive ions / forms zinc ions (1)
Hydrated cobalt chloride formula
CoCl2.6H2O
Name starting materials added to the blast furnace
limestone, coke, hot air, iron ore
Reaction of calcium oxide and silicon oxide in blast furnace
Neutralisation reaction
CaO + SiO2 -> CaSiO3
What is mixed with iron other than carbon to make stainless steel
Nicket/chromium
Chemical name of rust
hydrated iron (III) oxide
Methods of preventing rust that aren’t galvanising
Painting, greasing, coating with plastic
Steps that student should take in preparing a pure sample of lead (II) chloride from the mixture in the beaker
- Filter the precipitate
- Wash the residue with distilled water
- Dry the residue in between filter papers
Explain the apparent unreactivity of aluminium
M1 aluminium oxide layer (1)
M2 (oxide layer) is unreactive (1)
Explain in terms of thermal energy how greenhouse gases cause global warming (3)
M1 greenhouse gases absorb thermal energy (from the Earth) (1)
M2 and M3 one mark each for any two of:
* energy (from the sun) absorbed by Earth’s surface
* Earth emits or reflects thermal energy
* (greenhouse gases) reduces or stops thermal energy loss (into space)
* increasing in amount of greenhouse gas results in a higher atmospheric temperature
Two conditions needed for fermentation of aqueous glucose
- absence of oxygen
- presence of yeast
Typical temperature and pressure used for addition of steam to ethene
Temperature: 300
Pressure: 60 atm (6000 kPa)
State the meaning of weak in weak acid
partially disassociate
Name the oxidising agent for ethanol to ethanoic acid
acidified potassium manganate (VII)
Name the process for ethene to ethanol
catalytic addition
Explain in terms of structure and bonding why graphite has a much higher melting point
than carbon monoxide
M1 graphite has a giant covalent structure
M2 attraction between molecules in carbon monoxide
M3 weaker attraction (between particles) in carbon monoxide ORA
State what is meant by the term electrolysis
M1 breakdown by (the passage of) electricity
M2 of an ionic compound in molten or aqueous (state)
Write an ionic half-equation for the production of oxygen at the anode
4OH– → 2H2O + O2 + 4e–
To make soluble salt react dilute acid and insoluble base (carbonate, oxide, hydroxide)
State why the student keeps heating until mass is constant
To ensure all water is given off
Explain, in terms of electrons, why magnesium is used for sacrificial protection for steel
M1 magnesium loses electrons more readily than / in preference to / instead of iron
M2 magnesium is more reactive than iron ORA
Alkenes are produced by cracking alkanes.
When C12H26 is cracked, the products are ethene and an alkane which form in a 2:1 mole ratio.
Write a symbol equation for this reaction
C12H26 -> 2C2H4 + C8H18
