Column Alpha
Name the substance used to remove sulfur dioxide in flue gas desulfurisation.
calcium oxide
Lithium, sodium and potassium are Group I elements.
Name the type of bonding in these elements.
Metallic (bonding)
State the class of oxide to which copper(II) oxide belongs.
basic (oxide)
Explain why members of a homologous series have similar chemical properties.
same functional group
Ammonia reacts with an acid to form ammonium sulfate, (NH4)2SO4.
State the formula of the acid used.
H2SO4
Methanoic acid is represented by the formula HCOOH.
Name this type of formula.
structural
Name a halide compound which can be used to detect the presence of water.
anhydrous cobalt(II) chloride
Name two forms of the element carbon which have giant covalent structures.
Graphite and diamond
Suggest why universal indicator is not suitable for titration.
too many colour changes
Chloroethene monomers can be converted into a polymer called poly(chloroethene).
State the type of polymerisation that produces poly(chloroethene) from chloroethene.
addition
State two reasons why carbon (graphite) is suitable to use as an electrode.
Inert
Good conductor of electricity
Sodium hydrogensulfate, NaHSO4, dissolves in water to produce an aqueous solution, X, containing Na+, H+ and SO42– ions.
State the observations when copper(II) oxide is warmed with an excess of X.
blue solution(1)
solid dissolves / disappears(1)
Complete the chemical equation to show the formation of ethene from decane, C10H22.
C10H22 → C4H8 + ................... + ...................
→ C2H4 + C4H10 (2)
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 electrical conductivity of the electrolyte
M2 lower operating temperature
Describe the test for an unsaturated hydrocarbon.
aqueous bromine (1)
turns colourless / decolourises (1)
Amino acids are colourless.
A sample containing a mixture of amino acids is separated. Each amino acid is detected and identified.
a) Name the process used to separate the amino acids.
b) Name the type of substance used to detect the amino acids.
c) Give the symbol of the value used to determine the identity of each amino acid after separation and detection.
M1 chromatography (1)
M2 locating agent (1)
M3 Rf (1)
Proteins are natural polymers. Proteins contain amide linkages.
Synthetic polyamides also contain amide linkages.
a) Name a synthetic polyamide.
b) Identify the two monomers used to produce synthetic polyamides.
a) nylon
b) dicarboxylic acid, diamine
A metal spoon is electroplated with copper.
State what is used as:
a) the positive electrode (anode)
b) the negative electrode (cathode)
c) the electrolyte.
a) copper
b) spoon
c) aqueous copper(II) sulfate / copper(II) nitrate
Chlorine(I) oxide, Cl2O, is a simple molecule with covalent bonds.
Explain, in terms of structure and bonding, why Cl2O boils at a low temperature and does not thermally decompose into its constituent elements, Cl2 and O2.
M1 (forces of) attraction between molecules are broken (during boiling)
M2 covalent bonds (between Cl and O atoms) are broken (during thermal decomposition)
M3 weak attraction between molecules and strong covalent bonds
(NH4)2Cr2O7 is a compound containing chromium.
The negative ion in (NH4)2Cr2O7 is Cr2O72–.
a) State the sum of the oxidation numbers in the Cr2O72– ion.
b) The oxidation number of each O in Cr2O72– ions is –2.
Determine the oxidation number of each Cr in Cr2O72– ions. Show your working.
a) -2
b) +6
Describe the observations when potassium is added to cold water. Write a balanced equation for the reaction. Include state symbols.
any 2 observations from:
solid moves / floats
solid dissolves / disappears
bubbles / effervescence / fizzes
lilac flame
explodes
melts / forms a spherical shape
2K(s) + 2H2O(l) →2KOH(aq) + H2(g)
Nitrogen reacts with hydrogen to form ammonia, NH3, in the Haber process.
State the essential conditions in the Haber process. Write an equation for the chemical reaction.
450 °C (1)
200 atmospheres (1)
iron catalyst (1)
N2 + 3H2 ⇌ 2NH3 (1)
Alkali metals are reactive elements.
Identify the alkali metal which:
a) has the highest melting point
b) has the highest density
c) has the lowest reactivity
d) burns with a lilac flame
e) is found in fertilisers to improve plant growth.
lithium / Li
francium / Fr
lithium / Li
potassium / K
potassium / K
Ethene, C2H4, is the first member of a family of similar compounds which contains the alkene functional group.
a) State the term for a family of similar compounds which contain the same functional group.
b) Determine the difference in relative molecular mass between C2H4 and the next member in this family of similar compounds.
c) Write the symbol equation for the complete combustion of C2H4.
a) homologous series
b) 14
c) C2H4 + 3O2 → 2CO2 + 2H2O
Name the products and state the observations at the negative and positive electrodes when dilute aqueous potassium bromide, KBr, undergoes electrolysis.
product at negative electrode: hydrogen
observation at negative electrode: bubbles
products at positive electrode: oxygen and water
observation at positive electrode: bubbles