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7/31/2019 Scheme Mid Year Exam f42012
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Question Description Marks1 ( a )
( i )
Bottom test tube touch the beaker 1
1 ( a ) ( ii
)
Even /uniform heating 1
1 ( a )
( iii )
80C 1
1 ( a )
( iv )
Solid and liquid 1
1 ( a ) ( v
)
At E kinetic energy is low , at F kinetic energy increase 1
1 ( a )
( vi )
60C 90C
Minimum 3 layers
No overlapping between atoms
2
1 ( b ) Process : diffusion
Explanation: particles move randomly // freely
From higher concentration region to lower
concentrationregion
1
1
1
2 ( a )
( i )
Bromine and phenol 1
2 ( a ) ( ii
)
Liquid 1
2 ( a )
( iii )
Nickel 1
2 ( a )
( iv )
1
2 ( a ) ( v
)
Ion 1
2 ( b )
( i )
P : Liquid S: Solid 2
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2 ( b ) ( ii
)
1
2 ( b )
( iii )
Particles of Q held together by weak intermolecular forces //
A small / less amount of energy required to the forces
1
2 ( b )
( iv )
1
3 ( a ) Proton , electron , neutron 13 ( b )
( i )
Total number of proton and neutron in the nucleus of an atom
Reject : neutron numbers
1
3 ( b ) ( ii
)
17
3 ( c )
( i )
Y24
121
3 ( c ) ( ii
)
1 1
3 ( d ) 1
3 ( e )
( i )
Atoms of the same element which have same number of proton
but different number of neutron // came proton number but
different nucleon number
1
3 ( e ) ( ii
)
W and X 1
3 ( f ) Group 16 , period 2 24 ( a ) Volume = 0.06 dm3
No of moles =24
06.0= 0.0025 mol
1
1
4 ( b )
( i )
No of molecules = 231002.60025.0
= 2110505.1 molecules
1
4 ( b ) ( ii 2110515.4 atoms 1
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5 ( d )
6 ( a ) W : Sulphuric acid // hydrochloric acid
Y : Zinc // Magnesium // Aluminium
Z : Anhydrous calcium chloride
1
1
16 ( b ) Collect the gas from the small hole in the test tube
and put a burning wooden splinter in test tube
No pop sound produced
1
16 ( c ) Copper : 1.16 g Oxygen : 0.29 g 16 ( d )
Empirical formula = XO // CuO
1
1
6 ( e ) No reaction happened 1 [ free
mark]6 ( f ) Cannot
Magnesium is reactive metal
1
1
SECTION B
Question Description Marks7 ( a ) ( i ) 18 and 20 respectively 17 ( a ) ( ii )
Similarities Differences1. having same proton number /number of electrons
1. different in the numberof neutron / nucleonnumber
2.having same valence electron/ have same chemicalproiperties
2. different in physicalproperties
1
1
7 ( b ) ( i ) Group 14 , period 2 17 ( b ) ( ii ) Nucleus contains 6 proton and 6 neutron 1
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Electrons move around the nucleus
Two shells filled with electrons
There are 6 valence electrons // electron arrangement 2.4
[accept any other suitable answers]
1
1
1
Max : 3
7 ( b ) ( iii )
Comparison Diagram
7.2
S atom
Proton number 6 6Number of valence electron 4 4Chemical properties similar SimilarNumber of neutron // nucleon
number
6 // 12 7 // 13
Physical properties Different DifferentStandard representation of element different different
Any 4
7 ( c ) ( i )
7 ( c ) ( ii ) Substance X in both solid and liquid state
Heat energy is released
Kinetic energy of particles decreases
They are closer to each other // attraction force between
particles become stronger
1
1
1
1
8 ( a ) Number of mole in 16 g of oxygen = 16/32 // 0.05 mol
Volume occupied by 16 g of oxygen = 2405.0 // 12 dm3
Number of mole in 22g of CO2 = 22/44 // 0.05 mole
Volume occupied by 22g of CO2 = 2405.0 // 12 dm3
1
1
1
18 ( b ) Able to determine empirical formula and molecular formula
correctly
Element C H N OMass /g 0.48 0.05 0.28 0.16No of mole 0.48/12
//0.04
0.05/1
//0.05
0.28/14
//0.02
0.16/16
//0.01Simplest ratio no of
mole
0.04/0.
01
//4
0.05/0.
01
//5
0.02/0.
01
//2
0.01/0.
01
//1
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2. a thermometer is placed into powder of compound M in the
boiling tube
3. a 500ml beaker is filled with coconut oil / palm oil until full
4. the beaker is then placed on a tripod stand
5. the boiling tube containing compound M is clamped onto a
retort stand and immersed into the coconut oil / palm oil in the
beaker
6. the coconut oil / palm oil is heated slowly and the stopwatch
is started
7. the powder of compound M is stirred slowly with the
thermometer
8. the temperature of the compound M is recorded at 30
seconds intervals until the compound M has melted completelyResult :
The temperature reading are recorded in a table as shown
below.
The graph of temperature against time for the heating of
compound M is plotted
Conclusion:
Based on the graph, the temperature remains constant at TC
(must indicate T in the graph)
Therefore, the melting point of compound M is TC
1
1
1
1
1
1
Max : 6
1
1
1
1
10 ( a ) Molecular formula is a formula that shows the actual no of
atom of each element in the compound
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10 ( b )
10 ( c ) Procedure :
1. clean magnesium ribbon with sand paper
2. weigh crucible and its lid
3. put magnesium ribbon into the crucible and weigh the
crucible with its lid
4. heat strongly the crucible without its lid
5. cover the crucible when the magnesium starts to burn and
lift / raise the lid a little at intervals6. remove the lid when the magnesium burnt completely
7. heat strongly the crucible for a few minutes
8. cool and weigh the crucible with its lid and the content
9. repeat the processes of heating , cooling and weighing until
a constant mass is obtained
10 record all the mass
11. results :
Description Mass (g)Mass of crucible + lid XMass of crucible + lid +magnesium
Y
Mass of crucible + lid +magnesium oxide
z
12. calculations :
Element Mg OMass (g) y x z yNumber of mole of
atoms 24
xy
16
yz
Simplest ratio ofmoles /
p q
1
1
1
1
1
11
1
1
1
1
1
1
1
1
Max :
12
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