Exam Qs Flashcards by Meher Singh

State why sewage and phosphates in river water is harmful (2)

sewage: contains microbes which cause disease (1)
phosphates: deoxygenation of water (1)

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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)

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State one source of the pollutant sulfur dioxide in the air other than from burning sulfur

combustion of fossil fuels (containing sulfur)

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the chemical name of SiO2

Silicon (IV) oxide

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State what is meant by the term covalent bond

pair of electrons shared between two atoms

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Name a halide compound which can be used to detect the presence of water

Anhydrous cobalt (II) chloride

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In the equation, methanoic acid is represented by the formula HCOOH.
Name this type of formula.

Structural

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When but-1-ene reacts with steam, two possible products form. Identify the type of catalyst which is used in this reaction

Acid

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State what is meant by the term closed system

nothing can enter or leave

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Two possible products when but-1-ene reacts with steam

But-1-ol, but-2-ol

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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)

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Temperature and pressure used in Haber process

450 degrees celsius
200 atm

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Which element in period 2 has the highest rate of diffusion?

Neon

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Which element in period 2 has the oxide responsible for acid rain?

Nitrogen

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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)

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Two observations in the reaction of calcium chloride and nitric acid

effervescence
solid dissolves/disappears

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Suggest what is meant by the term saturated solution

a solution that can contain no more solute at a given temperature

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Write the chemical equation for the reaction when solid sodium nitrate is heated (decomposition)

2NaNO3 -> 2NaNO2 + O2

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Bromine colour at room temp and bromine water colour

bromine by itself at room temp is red-brown but bromine water is orange

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Describe the arrangement of atoms in graphite (2)

M1 layers
M2 hexagon(al) (rings of carbon)

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Describe the process which converts metal ores to sulfur dioxide

strong heating in air / roasting in air

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Suggest the name for a solution in which no more solute can dissolve

saturated

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Suggest why more crystals of magnesium sulfate appear on cooling

solubility (of MgSO4 / solid) decreases (as temperature decreases)

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Write the chemical equation for the reaction when solid magnesium nitrate is heated (2)

2Mg(NO3)2 → 2MgO + 4NO2 + O2

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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

1. Sulfur burned in air 2. 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

1. absence of oxygen 2. 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