What’s in this book?What’s in this book? · PDF file(2015)1 H2 Chemistry chemistry 9647/01 higher 2 october/november 2015 Paper 1 Multiple Choice 1 hour AL H2 Yearly Edition Chemistry

Past Years Examination PapersSubject Code 9647 Years 2010 – 2015 Paper 1, Paper 2 and Paper 3

Subject Code 9746 / 9761 Years 2007 – 2009 Paper 1, Paper 2 and Paper 3

Supplement and Answer Booklet (Separate Booklet)Subject Code 9647 Years 2010 – 2015 Paper 1 answers with explanations, Tips and Common Mistakes alerts Papers 2 and 3 answers with workings and illustrations where

applicable, and Tips and Common Mistakes alerts

Subject Code 9746 / 9761 Years 2007 – 2009 Paper 1 answers with explanations, Tips and Common Mistakes alerts Papers 2 and 3 answers with workings and illustrations where

applicable, and Tips and Common Mistakes alerts

The Data booklet for chemistry, qualitative analysis notes and the Periodic table of the elements are included in the Answer Booklet to enable students to work on the questions effectively.

What’s in this book?What’s in this book?

AL H2 Yearly Edition Chemistry 21 1 5/11/2016 5:43:13 PM

Past Examinations Papers 1, 2 and 3

year 2015 .......................................................................................................... (2015)1 ~ 36

year 2014 .......................................................................................................... (2014)1 ~ 34

year 2013 .......................................................................................................... (2013)1 ~ 34

year 2012 .......................................................................................................... (2012)1 ~ 34

year 2011........................................................................................................... (2011)1 ~ 36

year 2010 .......................................................................................................... (2010)1 ~ 38

year 2009 .......................................................................................................... (2009)1 ~ 38

year 2008 .......................................................................................................... (2008)1 ~ 34

year 2007 .......................................................................................................... (2007)1 ~ 32

Supplement and Answers (Separate booklet)

Data Booklet and The Periodic Table of the ElementsYears 2007-2015, Papers 1, 2 and 3

CONTENTSCONTENTS


(2015)1H2 Chemistry

chemistry 9647/01higher 2 october/november 2015Paper 1 Multiple Choice 1 hour


(2015)2H2 Chemistry


(2015)16H2 Chemistry

chemistry 9647/02higher 2 october/november 2015Paper 2 Structured Questions 2 hours





chemistry 9647/03higher 2 october/november 2014Paper 3 Free Response 2 hours




H2 cHemistry eXAmiNAtiON yeAr 2015

PAPER 1Section A�. B [2: Atomic Structure]

TheelectronicconfigurationforGroupIVelementwould be either �s22s22p2 or �s22s22p��s2�p2.The four electrons of highest energy refer to theelectrons at shells with highest principal quantumnumber.

An atom is in the ground state when the electrons are in the orbitals of lowest available energy level. Most atoms are in their ground state at room temperature. This is different from the excited state where one or more electrons absorb energy and are promoted to a higher energy level.

Tips

2. B [�: Chemical Bonding]σbondsareformedviahead-onoverlapbetweentwo s orbitals, two p orbitals and between one sandoneporbitals.Inhydrocarbons,thecarbonatoms have hybrid orbitals (could be sp, sp2 or sp�

hybridised) made up of s and p orbitals. Hence,σbondscanbeformedbyeithersorporbitals.�bondscanonlybeformedbyside-wayoverlapbetween two p orbitals.

�. C [2: Atomic Structure]Oxygen atom has � electrons while hydrogenatom has � electron. Since hydroxide anion hasan extra electron gained, the total number ofelectrons is � + � + � = �0. Oxygen atom has �neutrons while hydrogen atom has no neutrons.Hence, the total number of neutrons in hydroxideanion is � + 0 = �.

�. C [�: Chemical Bonding]A higher charge on Ca2+ ion would mean thatthe electrostatic forces of attraction between thecation and the sea of delocalised valence electronsare stronger as compared to Na+ ion.

Option D is incorrect because even if Ca2+ ion has more electrons than Na+ ion, the electrons in the Ca2+ ion are not mobile.Itdoesnotexplainthestrongermetallicbondingincalcium which results in having a higher melting point. The correct explanation should be calcium metal has more mobile electrons than sodium metal, instead of their ions.

Common Mistakes

�. B [�0.�: Nitrogen Compounds]The –NH2 group in aminoethanoic acid moleculehas a trigonal pyramidal shape (bond angle �0�°)whereas the –NH�

+ group in its zwitterion has atetrahedral shape (bond angle �0�.�°).

H – N – C – C

H

H

H

H

O

O

N – C – C

H

H

H

H

O

O – H

:

trigonal pyramidal tetrahedral

aminoethanoic acid molecule

zwitterion of aminoethanoic acid

�. D [�: Chemical Energetics]Lattice energy is defined as the heat energyevolved when one mole of solid ionic compoundis formed from its constituent gaseous ions.

�. B [�: Atoms, Molecules and Stoichiometry]

Mole of NaOH = 0.0�00 × �2.�_____�000

= �.2� × �0–� mol

Mole of HCl = 0.�00 × 2�.0 _____ �000 = 2.�0 × �0–� mol

Based on equation: HCl+NaOH→NaCl + H2ONaOH is the limiting reagent while HCl is inexcess.Mole of HCl remaining= 2.�0 × �0–� mol – �.2� × �0–� mol= �.�� × �0–� molTotal volume of solution= �2.� cm� + 2�.0 cm�

= ��.� cm�

Concentration of HCl remaining

= Mole of HCl remaining

____________________ Total volume of solution

= �.�� × �0–�__________( ��.� _____�000 )

= 0.0500 mol dm–3

�. C [�: Atoms, Molecules and Stoichiometry]CH� + 2O2→CO2 + 2H2O

CH� + � __ 2 O2→CO+2H2O

�CH� + ��O2→9CO2 + ��H2O

CH� + � __ 2 O2→CO+2H2O

Therefore, �0 moles of CH� react with �� + �.�= ��.� moles of O2 to produce � moles of CO2and � mole of CO (i.e. � : � mole ratio as givenin the question).Hence, �.�� dm� of O2 was needed to burn � dm�

of CH� in this gas burner.

Answers to A Level H2 Chemistry Yearly Edition© Singapore Asia Publishers Pte Ltd

A�Year 20��


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What’s in this book?What’s in this book? · PDF file(2015)1 H2 Chemistry chemistry 9647/01 higher 2 october/november 2015 Paper 1 Multiple Choice 1 hour AL H2 Yearly Edition Chemistry