Answer Chemistry Perfect Score & X A Plus Module 2013

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Answer Chemistry Perfect Score & X A Plus Module 2013 

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<p>@Hak cipta BPSBPSK/SBP/2013 1 Perfect Score &amp; X A Plus Module/mark scheme 2013 BAHAGIAN PENGURUSAN SEKOLAH BERASRAMA PENUH DAN SEKOLAH KLUSTER JAWAPAN MODUL PERFECT SCORE &amp; X A-PLUS 2013 CHEMISTRY Set 1 Set 2 Set 3 Set 4 Set 5 http://cikguadura.wordpress.com/CHEMISTRY @Hak cipta BPSBPSK/SBP/2013 2 Perfect Score &amp; X A Plus Module/mark scheme 2013 MODULE PERFECT SCORE &amp; X A-PLUS 2013 SET 1 :THE STRUCTURE OF ATOM, PERIODIC TABLE OF ELEMENTS AND CHEMICAL BONDS Question No Mark schemes Mark 1 (a) (i) Melting 1 (ii) Molecule 1 (b) The heat energy absorbed by the particles is used to overcome the forces of attraction between the naphthalene molecules / particles. 1 (c) The particles move faster 1 (d) (i) X : electron Y : nucleus 1 (ii) Electron 1 (e) (i) W and X 1 (ii) W and X atom have different number of neutrons but same number of protons Atom// Element W and X has different nucleon number but same proton number 1+1 10 Question No Mark schemes Mark 2 (a) No of electrons = 18, No of neutrons = 22 1+1 (b) (i) The total number of protons and neutrons in the nucleus of an atom 1 (ii) 40 (c) (i) 2.1 1 (ii) X (d) (i) W and Y 1 (ii) Atom W and Y have the same number of valence electrons 1 (iii) To estimate the age of fossils /artefacts. 1 10 X X e 3p 4n X e e X http://cikguadura.wordpress.com/ @Hak cipta BPSBPSK/SBP/2013 3 Perfect Score &amp; X A Plus Module/mark scheme 2013 Question No. Mark Scheme Marks 3 (a) (i) Total number of protons and neutrons in the nucleus of an atom 1 (ii) 35 18 = 17 1 (iii) shows nucleus and three shells occupied with electron Label 12 proton, 12 neutron 1 +1 (iv) Number of electrons = 2 1 ...5 (b) (i) Liquid 1 (ii) Q R 1+1 ...3 (c) 1st mark - Label X and Y axis with correct unit 2 nd mark - Correct shape of curve 1+1 10 Temperature/o C Time/s 67 90 @Hak cipta BPSBPSK/SBP/2013 4 Perfect Score &amp; X A Plus Module/mark scheme 2013 4 a) (i) F 1 (ii) Atom F has achieve stable/octet electron arrangement // has 8 valence electron 1 b) (i) 2D + 2H2O 2DOH + H2 Correct reactant &amp; correct product Balance equation 1 1 (ii) The nuclei attraction towards the valence electrons is weaker in atom G. More easier for atom G to lose / release an electron to form a positively charged ion. 1+1 c) (i) Covalent bond 1 (ii) 1 1 (iii) Cannot conduct electricity at any state/ low melting and boiling point/.... 1 (d) Show coloured ion//formed complex ion//has various oxidation number//act as catalyst 1 11 5 (a) Increasing of proton number. 1 (b) (i) Na/sodium, Mg/magnesium .... 1 (ii) Atomic size decreases across the period // Period 3. 1 (iii) 1. Number of protons in atom increases when across the period. 2. Force of attraction between nucleus and electrons in the shell is stronger. 1+1 ..4 (c) Chlorine more reactive than bromine Size of chlorine atom is smaller than bromine atom Chlorine atom is easier to receive one electron 1+1 (d) Al3+ 1 (e) (i) Ionic compound 1 (ii) 1+1 11 Y Yx X x x x x x E EY @Hak cipta BPSBPSK/SBP/2013 5 Perfect Score &amp; X A Plus Module/mark scheme 2013 6 (a) P : liquid Q : solid R : gas 1 +1+1 (b) (i) 1. P can be change to Q through freezing process. 2. When the liquid cooled, the particles in liquid lose energy and move slower. 3. As temperature drops, the liquid particles attract tone another and change into solid 1 1 1 (ii) 1. P can change to R through boiling. 2. When liquid is heated, the particles of the liquid gain kinetic energy and move faster as the temperature increase 3. The particles have enough energy to overcome the forces between them and gas is formed 1 1 1 (iii) 1. R can be change to P through condensation process. 2. When the gas cooled, the particles in gas lose energy and move slower. 3. Particles attract one another and change into liquid 1 1 1 (c) (i) 1. Uniform scale for X-axis and Y-axis and labelled/size of graph plotted of graph paper. 2. Tranfer of point 3. Smooth curve 1 1 1 (ii) 1. Dotted line on the graph from the horizontal line to Y-axis at 80o C. 2. Arrow mark freezing point at 80o C 1 1 (iii) 1. Heat released to sorrounding 2. Is balanced when particles comes together to form a solid 1 1 (iv) Supercooling 1 20 @Hak cipta BPSBPSK/SBP/2013 6 Perfect Score &amp; X A Plus Module/mark scheme 2013 Question No. Mark Scheme Mark 7 (a) (i) Atom R is located in Group 17, Period 3 1 + 1 (ii) Electron arrangement of atom R is 2.8.7. Group 17 because it has seven valence electron. Period 3 because it has three shells filled with electron 1 1 1 (b) (i) Atoms P and R form covalent bond. To achieve the stable electron arrangement, atom P needs 4 electrons while atom R needs one electron. Thus, atom P shares 4 pairs of electrons with 4 atoms of R, forming a molecule with the formula PR4 // diagram 1 1 1 1 1 (ii) Atom Q and atom R form ionic bond. Electron arrangement for atom Q is 2.8.1 and electron arrangement for atom R is 2.8.7// Atom Q has 1 valence electron while atow R has 7 valence electron To achieve a stable (octet ) electron arrangement, atom Q donates 1 electron to form a positive ion// equation Q Q+ + e Atom R receives an electron to form ion R- //equation and achieve a stable octet electron arrangement. R + e R- Ion Q+ and ion R- are attracted together by the strong electrostatic forces to form a compound with the formula QR// diagram 1 1 1 1 1 1 R R R R P Q R + - - @Hak cipta BPSBPSK/SBP/2013 7 Perfect Score &amp; X A Plus Module/mark scheme 2013 Question No Mark scheme Mark 8 (a) 12 represents the nucleon number. 6 represents the proton number. 1 1 (b) Able to draw the structure of an atom elements X. The diagram should be able to show the following informations: 1. correct number and position of proton in the nucleus/ at the centre of the atom. 2. correct number and position of neutron in the nucleus/ at the centre of the atom. 3. correct number and position of electron circulating the nucleus 4. correct number of valence electrons Sample answer: or 1 1 1 1 e- e- e- e- e- e- e- e- e- e- e- 11p 12n 1 2 3 4 e- e- e- e- e- e- e- e- e- e- e- 11p + 12n @Hak cipta BPSBPSK/SBP/2013 8 Perfect Score &amp; X A Plus Module/mark scheme 2013 (c) (i) Atoms W and Y form covalent bond. To achieve the stable electron arrangement, atom W contributes 4 electrons while atom Y contributes one electron for sharing. Thus, atom W shares 4 pairs of electrons with 4 atoms of Y, forming a molecule with the formula WY4 // diagram 1 1 1 1 1 (ii) Atom X and atom Y form ionic bond. Electron arrangement for atom X is 2.8.1 and electron arrangement for atom Y is 2.8.7 To achieve a stable (octet )electron arrangement, atom X donates 1 electron to form a positive ion // equation X X+ + e Atom Y receives an electron to form ion Y- //equation and achieve a stable octet electron arrangement. Y + e Y- Ion X+ and ion Y- are attracted together by the strong electrostatic forces to form a compound with the formula XY// diagram 1 1 1 1 1 1 (d) The melting point of the ionic compound/ (b)(ii) is higher than that of the covalent compound/ (b)(i) . This is because in ionic compounds oppositely ions are held by strong electrostatic forces. High energy is needed to overcome these forces. In covalent compounds, molecules are held by weak intermolecular forces. Only a little energy is required to overcome the attractive forces. OR The ionic compound/(b)(ii) conducts electricity in the molten or aqueous state whereas the covalent compound/(b)(i) does not conduct electricity. This is because in the molten or aqueous state, ionic compounds consist of freely moving ions carry electrical charges. Covalent compounds are made up of molecules only 1 1 1 1 1 or 1 1 1 1 1 20 X Y + - - Y Y Y WY @Hak cipta BPSBPSK/SBP/2013 9 Perfect Score &amp; X A Plus Module/mark scheme 2013 9 (a) (i) 1. Correct number of shells and valence electrons 2. Black dot or label Q at the center of the atom 1 1 (ii) 1. Group 14 2. There are 4 valence electrons 3. Period 2 4. Atom consists of 2 shells occupied with electrons 1 1 1 1 (b) (i) 1. Floats and moves fast on the water 2. Hiss sound occurs 3. Gas liberates / bubble [any two] 1 1 (ii) 2Q + 2H2O 2QOH + H2 1. Correct reactant and product 2. Balanced equation 1 1 (c) (i) Compound X Sharing electron between atom B and A 1 1 (ii) Choose any one ionic compound and any one covalent compound. Melting/boiling point Ionic compound Covalent compound 1. 2. 3. High force of attraction between oppositely charged ions are strong. more heat energy needs to overcome the forces. low force of attraction between molecules are weak. less heat energy needs to overcome the forces. 1 1 1 1 Electrical conductivity Ionic compound Covalent compound 4. 5. Conduct in molten state or aqueous solution. The free moving ions are able to carry electrical charges. Not conduct electricity. Neutral molecules are not able to carry electrical charges. 1 1 1 1 Solubility Ionic compound Covalent compound 6 7 Soluble in water. Water molecule is polar solvent. soluble in benzene/ toluene / any organic solvents. The attraction forces between molecules in solute and solvent are the same. 20 Q @Hak cipta BPSBPSK/SBP/2013 10 Perfect Score &amp; X A Plus Module/mark scheme 2013 10 (i) Compound formed between X and Y Molecule formed between Z and Y Types of chemical bonds Ionic bond is formed because X atom donates electrons and Y atom receives electrons to achieve stable octet electron arrangement/involve transfer electron Covalent bond is formed because Z and Y atoms share the electrons to achieve stable electron arrangement // Inovelve sharing of electron Boiling point and melting point High because a lot of heat energy needed to overcome the strong electrostatic forces between ions Low because less heat energy is needed to overcome the weak forces of attraction between molecules 2 2 (b) 1.Correct electron arrangement of 2 ions 2.Correct charges and nuclei are shown 3. X atom with an electron arrangement of 2.8.2 donates 2 valence electrons to achieve the stable octet electron arrangement, 2.8. X2+ ion is formed // X X2+ + 2e- 4. Y atom with an electron arrangement of 2.6 accept 2 electrons to achieve the stable octet electron arrangement, 2.8. Y2- ion is formed // Y + 2e- Y2- 5. The oppositely-charged ions, X2+ and Y2- are attracted to each other by a strong electrostatic force. 6. An ionic compound XY is formed 1 1 1 1 1 1 1 X X X X X X X X X X XX X X X X X X X 2+ 2- X2+ Y2- X X X X X X X X X X XX X X X X X X X @Hak cipta BPSBPSK/SBP/2013 11 Perfect Score &amp; X A Plus Module/mark scheme 2013 (c) 1. A crucible is filled with solid P until it is half full. 2. Two carbon electrodes are dipped in the solid P and connected to the batteries using connecting wire. 3. Switch is turned on and observation is recorded. 4. The solid P is then heated until it melts completely. 5. The switch is turned on again and observation is recorded. 6. Steps 1 to 5 are repeated using solid Q to replace solid P. 7. Observations: P does not light up the bulb in both solid and molten states. Q lights up the bulb in molten state only. P: naphthalene // any suitable answer Q: lead(II) bromide // any suitable answer 1 1 1 1 1 1 1 1 1 1 1 1 1 20 11 (a) (i) Z : 2.8.7 X : 2.4 1 1 ..2 (ii) Z atom has 7 valence electrons needs one electron X atom has 4 valence electrons ,hence it needs 4 more electron each atom achieves stable octet electron arrangement share electrons between them four Z atoms , each contributes 1 electron // [ diagram one X atom contributes 4 electrons //[diagram] - four single covalent bonds are formed - the molecular formula is XZ4 - diagram [ no. of electrons in all the occupied shells in the X and Z atoms - correct] [ sharing of 4 pairs of single covalent bonds between 1 X atom and 4 Z atoms ] 1 1 1 1 1 1 1 1 1 1 ..10 (iii) Colourless liquid 1 b) [Procedures of the experiment] eg. 1. Add a quarter of spatula of YZ solid and add into a test tube. 2. Pour 2-5 cm3 of distilled water into the test tube containing theYZ2 3. Stopper the test tube and shake well. 4. Repeat Steps 1 to 3 using [ named organic solvent eg ether ] 5. Observe the changes and record them in a table 1 1 1 1 1 . [Results] Eg Solvent Observation Distilled water Colourless solution obtained [named organic solvent] e.g ether Solid crystals insoluble in liquid [Conclusion] eg ZY is insoluble in organic solvent/[named organic solvent] but soluble in water. 1 1 ..7 @Hak cipta BPSBPSK/SBP/2013 12 Perfect Score &amp; X A Plus Module/mark scheme 2013 No Explanation Sub Total 12 (a)(i) Y more reactive 1 5 Atomic size of Y bigger than X // The number of shell occupied with electron atom Y more than X. 1 The single valence electron becomes further away from the nucleus. 1 the valence electron becomes weakly pulled by the nucleus. 1 The valence electron can be released more easily. 1 (ii) Name : Sodium 4Na + O2 2Na2O Chemical formulae Balance equation 1 1 1 3 (b) Put group1 metal into bottle that contain paraffin oil Group 1 metal readily reacts with air/moisture in atmosphere/ water 1 1 2 (c) Name : Sodium/any group 1 element Material : group 1 elements, water, Apparatus : forceps , knife, filter paper, basin, litmus paper. 1 1 [procedure] 3. Pour some water into the basin 4. Group 1 metal is take out from paraffin oil using forceps 5. A small piece of group 1 element is cut using a small knife 6. Oil on group 1 element is dried using a filter paper 7. The group 1 element is placed in the basin contain water. 8. Dip a red litmus paper into water 1 1 1 1 1 1 Max 5 [observation] 9. Color of red litmus paper turn to blue 1 [chemical equation ] Sample answer 2 Na + 2 H2O 2NaOH + H2 Chemical formulae Balance equation 1 1 Total 20 No Explanation ` Total 13. (a) Glucose // naphthalene // any solid covalent compound covalent Intermolecular forces are weak Small amount of heat energy needed to overcomes the forces 1 1 1 1 4 (b) X = 2.1 X = 2.2 Y = 2.7 // Y = 2.6 // 1. Suitable electron aranggement 2. Ionic bond 3. to achieve octet electron arrangement 4. One atom of X donates 1 electron to form ion X+ 5. One atom of Y receives an electron to form ion Y- 6. Ion X+ and ion Y- are attracted together by the strong electrostatic forces 1 1 1 1 1 1 1 7 (c) material and apparatus; compound XY, Carbon electrode, cell, wire, crucible, bulb/ammeter/galvanometer 1 @Hak cipta BPSBPSK/SBP/2013 13 Perfect Score &amp; X A Plus Module/mark scheme...</p>