Khalifah Essay Example

Khalifah Essay Answer Horizontal row of elements in the Periodic Table of Elements Atoms have 3 shells occupied with electron 1. Correct formulae of reactants and products 2. Balanced equation Cl2 + H2O HCl + HOCl Sodium Chlorine Red litmus paper blue Blue litmus paper red http://cikguadura. wordpress. com Mark 1 1 1 1 (ii) 2 4541/2  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 3 Answer 1. Atomic size decrease 1. Proton number / number of proton / nuclei charge increase 2 Nuclei attraction on valence electron is stronger TOTAL 4541/2 Mark 1 No. (d)(i) (ii) 2 9 No. (a) Oxidation Answer Mark 1 1 1 1 1 1 (b)(i) To allow the movement / flow of ions (ii) (c) (d) Potassium nitrate solution [ any suitable substance] From copper electrode to silver electrode Intensity of blue colour solution increase Because the concentration /number of Cu2+ increase Cu (e) (f)(i) (ii) Cu2+ + 2e Formula of reactant and product Balanced Increase The distance between zinc and silver is further than copper and silver in electrochemical series TOTAL 1 1 1 1 10 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 4 4541/2 No. 4. (a) (b) Answer A chemical formula that shows the simplest ratio of atom of element in a compound. Number of mole = Mass Relative atomic mass Mark 1 1 (c)(i) (ii) (d) (e)(i) (ii) (iii) (iv) Num. of mole of copper = 2. 56 / 0. 04 64 Num. of mole of oxygen = 0. 64 / 0. 04 16 CuO Magnesium and hydrochloric acid / Zinc and sulphuric acid CuO + H2 ? Cu + H2O Black powder change to brown Water 2 1 1 2 1 1 TOTAL 10 No. 5(a)(i) (ii) Answer Temperature Num. of mole = 0. 24 mol / 0. 01 mol 24 Volume of H2 = 0. 01 x 24 dm3 / 0. 24 dm3 / 240 cm3 Mark 1 2 (b) Average rate of reaction in experiment I = 240 cm3s-1 / 4. 8 cm3s-1 50 Average rate of reaction in experiment II = 240 cm3s-1 / 12 cm3s-1 20 2 1 (c)(i) Rate of reaction of experiment II is higher than experiment I 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 5 4541/2 No. Answer Mark (c)(ii) -The temperature of reaction for experiment II is higher that experiment I. -The kinetic energy of the particles of reactants for experiment II is higher than experiment I. -The frequency of effective collisions increases. (d) 3 2 We will write a custom essay sample on Khalifah specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Khalifah specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Khalifah specifically for you FOR ONLY $16.38 $13.9/page Hire Writer TOTAL 11 No. 6(a) (b)(i) (ii) (iii) Answer To reduce the heat loss to the surroundings A shinny grey solid is formed / A colourless solution turns blue. Silver metal is formed / Copper(II) ions formed. Copper Oxidation number increase from 0 to +2 Mark 1 1 1 2 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 6 4541/2 No. (c)(i) Answer Num. of mole = 0. 5 x 100 / 0. 05 mol. 1000 Heat energy released = 0. 05 x 105 kJ / 5. 25 kJ / 5250 J Mark 2 1 (ii) ? = 5250 / 12. 5 oC 100 x 4. 2 (d) 1. Axis with label energy and two level, 2. Correct position of reactants and products, 3. ?H = -105 kJmol-1 1 1 1 TOTAL 11 3 No. 7 a (i) Answer Mark C p=6 n=8 1 [Draw and label] [Able to describe the atom Carbon-14] Has nucleus at the centre of the atom nucleus contains 6 proton and 8 neutron has 2 shell occupied electron 4 valence electrons 1 1 1 1 Max 4 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 7 4541/2 No. (ii) Answer Carbon-12// Carbon-13 6 // 7 12 C 6 // 13 C 6 Mark 1 1 1 . 3 1 1 1 . 3 (b)(i) P Boiling point P higher than melting point naphthalene Naphthalene is flammable ii) (c ) At time t1 – t2 Naphthalene is in liquid state The molecules are closely pack The molecules not in orderly arrangement The kinetic energy decrease At time t2 – t3 In liquid and solid state The molecules are closely pack Some molecules are in orderly arrangement but some are not in orderly arrangement. The kinetic energy is constant At time t3 – t4 In solid state Th e molecules are closely pack The molecules are in orderly arrangement Mark 1 + 1+ 1 1 1 + 1+ 1 The kinetic energy 1 + 1+ 1 decrease TOTAL 20 4541/2 http://cikguadura. wordpress. com Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 8 Sub Mark 1 1 1 1 1 1 1 1 1 1 4541/2 Mark No 8(a)(i) Answer Solvent X : Water / H2O Solvent Y : Propanone / Methyl benzene / [ any organic solvent] 2 (ii) 1. Hydrochloric in solvent X / water reacts with copper(II) oxide 2. Hydrochloric in solvent Y / propanone does not reacts with copper(II) oxide 3. Acid only shows its acidic properties when dissolve in water 4. In the present of water, hydrochloric acid ionize to form H+ ion 5. The H+ ion causes the hydrochloric acid reacts with copper(II) oxide // 6. H+ + CuO Cu2+ + H2O 7. Produce copper(II) chloride / Cu2+ ion 8. In propanone, hydrochloric acid exist as molecule // In propanone, H+ ion is not present 1. Neutralisation 2. Correct formulae of reactant and product 3. Balanced equation CuO + 2HCl CuCl2 + H2O 4. Number of mole of HCl = // 0. 05 8 (iii) 1 1 1 1 1 1 6 5. Number of mole of CuO = // 0. 025 mol 6. Mass of CuO = 0. 025 X (64 + 16) g // 2. 5 g (b) 1. Sodium hydroxide is a strong alkali // Sodium hydroxide ionises completely in water 2. Ammonia is a weak alkali // ammonia ionises partially in water 3. The concentration of hydroxide ions in sodium hydroxide is higher than in ammonia solution. 4. When the concentration of hydroxide ion is higher, the pH value is higher TOTAL 1 1 1 1 20 SULIT 4 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT No 9 (a) Answer General formula : CnH2n 9 4541/2 Mark n= 2,3†¦Ã¢â‚¬ ¦Ã¢â‚¬ ¦ 1 1 Functional group : Double bond between carbon atoms/ C=C Structural formula : [But-1-ene // But-2-ene] Example : 1 3 (b) C4H8 + H2O C4H9OH 1 1 Max 1 2 1 3 (c) 1. Y is unsaturated hydrocarbon 2. Y react with bromine 3. Butane is saturated hydrocarbon 4. Butane does not react with bromine Sample answer List of material : Butanol, [etanoic acid ], concentrated sulphuric acid Procedure : 1. Pour[2- 5 ]cm3 butanol into a boiling tube 2. Add [2- 5 ] cm3 of ethanoic acid . 3. Add 3 drops of concentrated sulphuric acid . 4. Heat the mixture carefully over a small flame 5. Boil the mixture slowly about 2 to 3 minutes. 6. Pour the content of the boiling tube into the beaker containing water 7. Smell the contents of the beaker. 8. Observation : Fruity smell substance produced 910 Chemical equation : C4H9OH + CH3COOH Correct formulae of reactants Correct ormulae of products 11. Name : Buthyl ethanoate CH3COOC4H9 + H2O 1 1 1 Max 10 Condition: Temperature : 300oC Pressure: 60 atm Catalyst: Concentrated Phosphoric acid 1 1 1 1 4 (d) 1 1 1 1 1 1 1 1 1 TOTAL 20 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 10 4541/2 No 10(a) Answer Acidic gases released in industries dissolved in rain water / water vapour to form electrolyte which increases the rate of rusting Sub Mark 1 1 1 1 Mark 2 (b) 1. Reaction I is not a redox reaction 2. No change in oxidation number for all elements before and after the reaction. / HCl + NaOH ? H2O + NaCl Oxidation No. +1-1 +1-2 +1 +1 -2 +1 -1 3. Reaction II is a redox reaction 4. Oxidation numbers of magnesium increases (from 0 to +2) and copper decreases (from + 1 to 0) // Mg (s) + Oxidation No. 0 (c) Step I Chemicals used Any suitable oxidising agent / e. g : Copper(II) sulphate solution II Any suitable reducing agent / e. g : zinc powder Observation Correct corresponding observation / Blue solution of Copper(II) sulphate solution becomes paler or colourless. Correct corresponding observation / zinc powder dissolves // brown colour of iron(III) ions becomes pale green. 1 4 CuSO4 (aq) ? MgSO4 + Cu +2 +2 0 1+1 1+1 4 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT SULIT 11 4541/2 (d) Sample answer ? Labeled diagram : 1. Functional apparatus 2. Label (consists of one reducing agent and one oxidizing agent in solution form separated by a salt bridge) Sample answer ? Procedure : 3. Filled the â€Å"U-tube† with dilute H2SO4 until 5 cm from the mouth of each arm 4. Add potassium iodide solution carefully to one arm and bromine water to another arm until 3 cm height 5. Immersed the carbon electrodes to each arm and connect to the galvanometer using connecting wire. 6. Record the observation. ?Half-equations involved : 7. Electrode in KI / Anode : 2 I ? I2 + 2e 8. Electrode in Br2 / Cathode : Br2 + 2e ? 2 Br ? Observation : 9. Electrode in KI / Anode : colourless solution of KI becomes brown 10. Electrode in Br2 / Cathode : Brown colour of bromine becomes colourless. TOTAL 20 1 1 1 1 1 1 1 1 1 1 10 END OF MARKING SCHEME 4541/2 http://cikguadura. wordpress. com  © Trial2011 Hak Cipta Sekolah Berasrama Penuh SULIT 1 SULIT MARKING SCHEME 4541/3 CHEMISTRY Paper 3 Question Rubric Able to state all observations correctly. Sample answer: Experiment I II 1(a) Able to state one observation correctly Able to state an idea of observation. Sample answer: Experiment I : air bubbles Experiment II : Size decreases No response or wrong response Question Rubric Able to state the inference correctly based on observation. Sample answer: Copper (II) ion / Cu2+ produced // Copper ionises // Copper released electron // Copper is oxidised. Able to state the inference incorrectly 1(b) Sample answer: Atom changed to ion. Able to state an idea of inference Sample answer: Copper changed // ion discharged No response or wrong response 2 Observation at anode Bubbles of gas released//effervescence occurs Copper / anode becomes thinner/ dissolved/ smaller. 3 Score 4541/3 1 0 Score 3 2 1 0 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. wordpress. com 2 SULIT Question Rubric Able to give the hypothesis accurately Sample answer: When copper electrodes are used instead of carbon electrodes, the types of products formed at the electrodes are different// Different electrode/anode produces different products. Able to give the hypothesis almost accurately Sample answer: Different products produce when different electrode/anode is used. Able to state an idea of hypothesis Sample answer: Different cells give different products// Electrode change/ affect/ influence product No response or wrong response Question Rubric Able to state the three variables correctly Sample answer: Manipulated variable : Type of electrode/anode // opper and carbon Responding variable : Product at the anode // Product of electrolysis Constant variable : Copper(II) sulphate//CuSO4// Electrolyte// Concentration of electrolyte r: Volume Able to state any two variables correctly Able to state any one variable correctly No response or wrong response Rubric Able to predict the product correctly Sample answer: Chlorine gas/ Cl2 Able to predict the product less accurately Sample answer: Halogen gas Able to state an idea of product. Sample answer: Greenish-yellow gas // Bubbles of gas// oxygen No response given / wrong respo nse 4541/3 Score 3 1(c) 2 1 0 Score 3 1(d) 2 1 0 Score 3 Question 1(e) 2 1 0 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. wordpress. com 3 SULIT Question Rubric Able to measure all the height of precipitate accurately with one decimal places. Answer: 1 2 3 4 5 6 7 0. 5 0. 9 1. 3 1. 6 2. 0 2. 0 2. 0 [0. 4[0. 8- [1. 2- [1. 5- [1. 9- [1. 9- [1. 90. 6] 1. 0] 1. 4] 1. 7] 2. 1] 2. 1] 2. 1] Able to write any 5 readings accurately // All readings correctly but without decimal places. Able to write any 3 readings correctly. No response given / wrong response Test tube Height of precipitate 4541/3 Score 2(a) 3 2 1 0 Question Able to draw the graph correctly i. i. iii. iv. Rubric Axis x : volume of barium chloride / cm3 and axis y : height of precipitate/ cm Consistent scale and the graph half of graph paper All the points are transferred correctly Correct curve Score 3 2(b) Able to draw the graph incorrectly 2 Axis x : volume of barium chloride and axis y : height of precipitate // Inverse axes ii. Consistent scale iii. About 5 points are transferred correctly iv. Correct curve Able to state an idea to draw the graph 1 i. Draw the axis x and axis y ii. Inccorrect curve. No response or wrong response i. 0 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. ordpress. com 4 SULIT Question Rubric Able to state the volume and calculate the number of mol correctly Answer: 1. 5 cm3 2. No. of mole = 0. 5 x 5 // 0. 0025 mol 1000 Able to state the volume correctly or calculate the number of mol correctly Sample answer: 5 cm3 // 0. 5 x 5 // 0. 0025 mol 1000 Able to state an idea to calculate Sample answer: 5// 0. 5 x 5 No response or wrong response 2 4541/3 Score 3 2(c) 1 0 Question Rubric Able to write the ionic equation correctly. Sample answer: Ba2+ + CrO42- ? BaCrO4 Able to write the ionic equation incorrectly. Sample answer: Ba2+ + CrO42- // BaCrO4 // Ba+ + CrO4- ? BaCrO4 Able to state an idea of writing equation. Sample answer: BaCl2 + K2CrO4 ? BaCrO4 + 2KCl No response or wrong response Score 3 2(d) 2 1 0 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. wordpress. com 5 SULIT Question Rubric Able to give the meaning of the precipitation reaction correctly. Sample answer: Yellow precipitate is formed when barium chloride solution reacts with potassium chromate (VI) solution. Able to give the meaning of the rate of reaction less accurately. Sample answer: Yellow precipitate is formed Able to give an idea of the rate of reaction. Sample answer: Double decomposition reaction No response given / wrong response 4541/3 Score 3 2(e) 2 1 0 Question Rubric Able to classify all the salts correctly Sample answer: Soluble salts Sodium carbonate, Na2CO3 Magnesium nitrate,Mg(NO3)2 Insoluble salts Lead(II)sulphate, PbSO4 Silver chloride, AgCl Score 3 2(f) Able to classify any three salts correctly Able to classify any two salts correctly or give opposite answers Sample answer: Insoluble salts Sodium carbonate, Na2CO3 Magnesium nitrate,Mg(NO3)2 Soluble salts Lead(II)sulphate, PbSO4 Silver chloride, AgCl 1 2 No response given / wrong response 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. wordpress. com 6 SULIT Question Rubric Able to give the aim of the experiment correctly. Sample answer : To compare the heat of combustion of different alcohols/(methanol, ethanol, propan-1-ol) Able to give a relevant idea with the problem statement or aim of the experiment. 3 (a) Sample answer : To de termine heat release when alcohols is burn// Does alcohol with a higher number of carbon atoms per molecule have a higher heat of combustion? // Does combustion release different quantity of heat? No response or wrong response 1 Score 4541/3 2 0 Question Rubric Able to state all variables correctly. Sample answer : Manipulated variable :Different type of alcohols// type of alcohols//methanol, ethanol, propan-1-ol Responding variable :Heat of combustion Score 3(b) Controlled variable :Volume of water// copper can// thermometer Able to state any two variables above correctly. Able to state any one variable above correctly. No response or wrong response 3 2 1 0 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. wordpress. com 7 SULIT Question Rubric Able to give the hypothesis of the experiment accurately. Sample answer : The higher the number of carbon atoms in the alcohol molecules, the higher the heat of combustion Able to give the hypothesis of the experiment correctly. Sample answer : The heat of combustion increases when the number of carbon per molecule of alcohol increases// Different types of alcohols have different heat of combustion// The larger the size of alcohols molecule, the higher the heat of combustion//when the molar mass of alcohol increases the heat of combustion increases. Able to give a relevant idea with the hypothesis of the experiment . Sample answer : Size/molar mass of alcohol molecule affect the heat of combustion. Number of carbon atom in alcohol affect the heat released in combustion// Alcohols have different heat of combustion. No response or wrong response 1 Score 4541/3 3 2 3(c) 0 Score Question Rubric Able to give the list of the materials and apparatus correctly and completely sample answer: Material: methanol, ethanol, propan-1-ol, water Apparatus :Copper can, tripod stand, thermometer, measuring cylinder, spirit lamp, weighing balance, wooden block, wind shield. Able to list out all he materials and the apparatus correctly but not completely Sample answer : methanol, ethanol, propan-1-ol, water Copper can, thermometer, spirit lamp, weighing balance. Able to give an idea about the list of the materials and the apparatus. Sample answer : Thermometer and any one substance No response or wrong response 3 3( d) 2 1 0 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. wordpress. com 8 SULIT Question Rubric Able to state all procedures correctly Sample answer : 1. 100 – 250] cm3 of water is measured and pour into a copper can. 2. The initial temperature of water is recorded. 3. The copper can is placed on a tripod stand. 4. A spirit lamp is filled with methanol and the initial mass is weighted and recorded. 5. The spirit lamp is put under the copper can and the wick of the lamp is lighted immediately. 6. The water is stirred with the thermometer until the temperature rises about 30oC. 7. The flame is put off and the highest temperature is recorded. 8. The spirit lamp and its content is weighed immediately and the final mass is recorded 9. Steps 1 to 8 are repeated using ethanol and propan-1-ol to replace methanol Able to list down steps 1,2, 4,5,7,8 and 9 2 Able to list down steps 2, 5 and 7 1 No response or wrong response 0 Score 4541/3 3(e) 3 Question 3(f) Rubric Able to tabulate the data with the following aspects: (i) Correct titles (ii) Correct unit (iii) Complete list of alcohols Types of alcohols Methanol Ethanol Propan-1ol Initial temperature/oC Highest temperature/oC Initial mass of spirit lamp/g Final mass of spirit lamp/g Score 3 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. ordpress. com 9 SULIT 4541/3 Able to tabulate the data with the following aspects: (i) Correct titles (ii) Complete list of alcohols Sample answer: Types of Initial alcohols temperature Methanol Ethanol Propan-1-ol Highest temperature Initial mass of spirit lamp Final mass of spirit lamp 2 Able to exhibit the tabulation of data less accurately Sample answer: Types of Initial alcohols temperature Me thanol 1 Ethanol Highest temperature No response or wrong response . 0 END OF MARKING SCHEME 4541/3  © 2011 Hak cipta Sekolah Berasrama Penuh Trial SPM 2011 http://cikguadura. wordpress. com