1. Choose from the following compounds to answer the questions.
Each compound may be used once, more than once or not at all.
(a) State which compound:
(i) has a molecule with only 14 atoms
................................................................................................................................... [1]
(ii) can be oxidised to form propanoic acid
.................................................................................................................................. [1]
(iii) is an isomer of butane
.................................................................................................................................. [1]
(iv) reacts with steam to make an alcohol
.................................................................................................................................. [1]
(v) can be polymerised to make a polyester.
................................................................................................................................... [1]
(b) State which two compounds in aqueous solution turn blue litmus red.
…………........................................................................................................................ [2]
2
(c) Compound D is used to make an addition polymer.
(i) Draw the structural formula of the polymer formed from 2 molecules of compound
D.
[2]
(ii) Give one problem caused by the disposal of addition polymers.
................................................................................................................................. [1]
[Total: 10]
3
2. (a) Complete the table to show the relative mass and relative charge of proton and a
neutron.
proton
electron
Relative mass
1
1840
Relative charge
-1
neutron
[2]
(b) Magnesium has three isotopes.
(i) State the meaning of the term isotopes.
......................................................................................................................................
.................................................................................................................................[2]
(ii) The symbol for an atom of one isotope of magnesium is
"#
!"Mg
Give the number of protons, neutrons and electrons in one atom of this isotope.
number of protons....................................................................................................[1]
number of neutrons .................................................................................................[1]
number of electrons .................................................................................................[1]
(iii) A sample of magnesium contains these percentages of the three isotopes.
Mg-24 = 79.00 %
Mg-25 = 10.00 %
Mg-26 = 11.00 %
Use this information to calculate the relative atomic mass of magnesium. Give your
answer to 2 decimal point.
[2]
[Total:9]
4
3. This question is about the reaction of Group I metals with water.
(a) A teacher adds a piece of sodium to some water containing universal indicator.
The equation for this reaction is
2Na(s) + 2H2O(l) à 2NaOH(aq) + H2(g)
The sodium floats on the surface of the water and the universal indicator changes colour
because an alkaline solution is formed.
(i) Give two other observations.
……………………………………………………………………………………………
……………………………………………………………………………………........[2]
(ii) Give the final colour of the universal indicator.
……………………………………………………………………………………........[1]
(b) The diagram represents an atom of lithium and an atom of sodium.
(i) Give a reason why lithium and sodium have similar reactions with water.
……………………………………………………………………………………. [1]
(ii) A student does a flame test to see if a white solid contains of lithium ions.
What is the colour of the flame if the solid contains lithium ions?
……………………………………………………………………………………..[1]
(c) Potassium sulfate is an ionic compound.
(i) Give the formula of each ion in potassium sulfate.
……………………………………………………………………………………..[2]
5
(ii) The melting point of potassium sulfate is 1069oC.
Explain why potassium sulfate has a high melting point. Refer to structure and
bonding in your answer.
………………………………………………………………………………………...
………………………………………………………………………………………...
………………………………………………………………………………………...
……………………………………………………………………………………..[3]
[Total :10]
4. A student uses this apparatus to investigate the rate of reaction between marble chips and
dilute hydrochloric acid.
The equation for the reaction is
CaCO3 + 2 HCl à CaCl2 + H2O + CO2
(a) During the reaction, the mass of the contents of the flask decreases.
(i) State why the mass of the contents of the flask decreases.
……………………………………………………………………………………. [1]
(ii) State the purpose of the cotton wool.
……………………………………………………………………………………. [1]
(iii) Explain why sulfuric acid is not suitable acid to use in this investigation.
………………………………………………………………………………………...
……………………………………………………………………………………..[2]
6
(b) The graph shows the student’s results.
(i) In the investigation the marble chips are in excess.
Explain the shape of the graph.
………………………………………………………………………………………..
………………………………………………………………………………………..
………………………………………………………………………………………..
…………………………………………………………………………………......[4]
(ii) The student repeats the experiment using the same volume of hydrochloric acid but
of half the concentration of the original acid. All other conditions are kept the same.
On the grid, draw the curve the student would obtain.
[2]
(c) Explain, using particle collision theory, how increasing the temperature affects the rate of
a reaction.
…………………………………………………………………………………………….
…………………………………………………………………………………………….
…………………………………………………………………………………………….
…………………………………………………………………………………………….
………………………………………………………………………………………….[4]
[Total:14]
7
5. This question is about copper and its compounds.
(a) Copper is a metal used for electrical wiring.
Explain why copper is a good conductor of electricity.
............................................................................................................................................
.........................................................................................................................................[2]
(b) This apparatus is used to investigate the electrolysis of copper(II) sulfate solution with
graphite electrodes.
Copper forms at the negative electrode and oxygen forms at the positive electrode.
(i) State what would be observed at each electrode.
negative electrode ..................................................................................................... [1]
positive electrode ...................................................................................................... [1]
(ii) The ionic half-equation for the reaction at the negative electrode is
Cu2+ + 2e– → Cu
State why this is a reduction reaction.
.......................................................................................................................................
....................................................................................................................................[1]
(iii) Explain why the copper(II) sulfate solution becomes paler blue during the
electrolysis.
.......................................................................................................................................
..................................................................................................................................[2]
8
(c) When hydrated copper(II) sulfate crystals, CuSO4•xH2O are heated, anhydrous copper(II)
sulfate forms.
A mass of 12.5 g of hydrated copper(II) sulfate crystals is heated in a crucible until all the
water of crystallisation is removed.
A mass of 8.0 g of anhydrous copper(II) sulfate forms.
[Mr of CuSO4 = 160; Mr of H2O = 18]
Determine the value of x using the following steps.
•
Calculate the number of moles of anhydrous CuSO4.
mole of CuSO4 = ………………….
•
Calculate the mass of H2O given off.
mass of H2O = ………………… g
•
Calculate the moles of H2O given off.
mole of H2O = ………………….
•
Determine the value of x.
x = ……………………….
[4]
[Total :11]
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6. This question is about metals.
(a) Metals can be arranged in a reactivity series based on their reactions with water and their
reactions with dilute hydrochloric acid.
The table shows how four metals, P, Q, R and S, react with water and with dilute
hydrochloric acid.
Metal
Reaction with water
P
Q
R
S
no reaction
no reaction
hydrogen gas forms very quickly
hydrogen gas forms quickly
Reaction with dilute
hydrochloric acid
hydrogen gas forms very slowly
no reaction
not done
hydrogen gas forms very quickly
(i) Identify which of the metals P, Q, R or S could be gold.
..................................................................................................................................[1]
(ii) Suggest why the reaction between metal R and dilute hydrochloric acid was not done.
..................................................................................................................................[1]
(iii) Use the information in the table to place the metals in order of reactivity from most
reactive to least reactive.
[1]
most reactive
least reactive
(b) zinc is used to coat iron gates to prevent the iron from rusting.
(i) Give the chemical name for rust.
..................................................................................................................................[1]
(ii) State the name of this method of preventing iron from rusting.
..................................................................................................................................[1]
10
(iii) State another method of preventing iron from rusting.
..................................................................................................................................[1]
(c) A mixture of zinc powder and copper(II) oxide is heated.
The chemical equation for the reaction that takes place is
Zn + CuO → ZnO + Cu
(i) State how the reaction shows that zinc is more reactive than copper.
........................................................................................................................................
....................................................................................................................................[1]
(ii) Explain which substance is the oxidising agent.
........................................................................................................................................
....................................................................................................................................[2]
[Total:9]
7. Crude oil is a mixture of hydrocarbons.
(a) Name the process used to separate crude oil into fractions.
………………………………………………………………………………………….[1]
(b) Give one use of the kerosene fraction.
………………………………………………………………………………………….[1]
(c) One of the hydrocarbons in the refinery gas fraction is an alkane with the structural
formula CH3CH2CH2CH3.
(i) Give the name of this alkane.
……………………………………………………………………………………..[1]
(ii) Calculate the relative molecular mass, (Mr)
Mr = …………………[1]
11
(d) One of the alkanes in the gasoline fraction has the structural formula
(i) Determine the molecular formula of this alkane.
……………………………………………………………………………………. [1]
(ii) Give the general formula for the alkanes.
…………………………………………………………………………………….. [1]
(e) Catalytic cracking is used to convert long-chain alkanes into shorter-chain alkanes.
(i) Name the catalyst used in catalytic cracking.
……………………………………………………………………………………. [1]
(ii) Explain why it is necessary to convert long-chain alkanes into shorter-chain
alkanes.
………………………………………………………………………………………...
………………………………………………………………………………………...
………………………………………………………………………………………...
……………………………………………………………………………………..[2]
(f) Catalytic cracking also produces alkenes.
C11H24 can undergo cracking to give pentane (C5H12) and two different alkenes.
Complete the equation for this cracking reaction.
C11H24 → C5H12 + .......................... + ............................
[2]
(g) This is the structural formula of an alkene, A.
(i) Give the name of alkene A.
………………………………………………………………………………………….[1]
12
(ii) Draw the structural formula of another alkene that is an isomer of A.
[1]
(h) An organic compound has the percentage composition by mass
C = 36.36%
H = 6.06%
F = 57.58%
(i) Show that the empirical formula of the compound is CH2F
[2]
(ii) The relative molecular mass (Mr) of the compound is 66.
Determine the molecular formula of the compound.
molecular formula = …………………. [2]
[Total:17]
Prepared by
: Lim Bee Lee
Checked by
13
: Lim Yee Hoong
14