Sec 1 Science SA2 St Josephs Convent 2018

lndex Number Class Name CHIJ ST JOSEPH'S CONVENT SEMESTRAL ASSESSMENT 2 o o sctENcE (cHEMTSTRY) Secondary 1 Express Friday, 5 October 201 8 50 minutes READ THESE INSTRUCTIONS FIRST Write your index number, class and name on all the work you hand in Write in dark blue or black pen. Do not use staples, paper clips, highlighters, glue or correction fluid. Section A There are ten questions. Answer all questions. For each question there are four possible answers A, B, C, and D. Choose the one you consider corect and shade your choice in the Multiple Choice Answer.Sheet with a 28 pencil. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Section B Answer all questions in the spaces provided The number of marks is given in brackets [] at the end of each question or part question Show all your workang on the same page as the rest of the answer. Omissron of essential working will result in loss of mirks. Electronic calculator may be used in this paper. The total of the marks for this paper is 40. A copy of the Periodic Table is printed on page 13 FOR EXAMINER'S USE A B 40 This document consists of !! printed pages Setter(s) : Mr Tan Keng Chiaw and Ms lzzati Jamil Sec 1 Erp Chemistry/SAzl8 [Turn Over I Total

2 1 Section A (10 marks) Answer all questions. "Amy drew a graph using the data she obtained from her experiments.,, Which step in the scientific inquiry process is the statement describing? analyzing results forming a hypothesis designing an experiment conducting an experiment Which of the following is the independent variable in this experiinent? the volume of air the color of the flame the height of the collar the location of the experiment An element is found to have the following properties . good electrical conductivity, .. shiny in appearance, . solid at room temperature. What is the element most likely to be? ' A boron B silicon C 'calcium D 'hydrogen Sec 1 Exp Chemrslry/SA2/1e 2 _ An experiment was conducted to investigate how the volume of air affects the colour' of the Bunsen burner flame. A B c D A B c D 3 4 w]ich of the forrowing statements best shows that coppe([) surfate sorution is amixture? A Copper(ll) sulfate solution is blue in colour. B Coppe(ll) sulfate is made up of different elements. C When heated, the water evaporates leaving a blue residue_ D No heat is released when coppe(ll) sulfate is dissolved in water.

5 3 Which of the underlined substance can be obtained through sublimation? salt from salt solution flour from flour suspension iodine from a mixture of iodine and salt water from a mixture of water and alcohol Two students carried out chromatography experiments to examine the dyes in a black ink. The chromatograms obtained by the students are shown below. solvent front They used the same black ink. Why are the chromatograms different? A One student did not use enough solvent. B The two students used different solvents. C The two students used different amount of black ink. D The solvent moved up the paper at different speeds. 7 ' Upon heating, the volume of a substance increases because I the size of particles increases. ll the number of particles increases. lll the space between particles increases lonly lll only ll and lll only l, ll and lll Sec I E)e Chem,stry/SAz18 A B c D 6 A B c D a I a a O a [Turn Over

4 8 The table below contains information on various elements element melting point fc) boiling point ('c) -220 -188 oxygen -219 - toJ nitrogen -210 chlorine -102 9 Particles of substance W slide over one another at -1g5 .C ldentify substance W. fluorine oxygen nitrogen chlorine The nuclide notation of a new substance Z found is l!Z Determine the number of electrons present in Z. A33 843 c76 D 109 10 Cobalt(ll) acetate has the chemical formula of Co(CHaCOO)2. How many atoms are'in cobalt(ll) acetate? 4 I 15 16 A B c D A B c D Sec 1 Exp Chem'stry/SA2/18 fluorine -196

5 Section B (30 marks) Answer all questions in the spaces provided. 1 A student conducted an experiment to react magnesium and hydrochloric acid (a) The following diagram shows the hazard symbols found on- bottles of magnesium and hydrochloric acid respectively. magnesium hydrochloric acid Suggest one safety precaution the student should take when handling each of the chemical. magnesium hydrochloric acid (b) Hydrogen gas, whieh is insoluble in water and less dense than air, is produced during the reaction. A student wanted to collect the hydrogen gas but did not have a gas syringe. Complete the experimental set-up below (with labels) that the student can use to collect hydrogen gas. hydrogen gas magnesrum hydrochloric acid 121 l2l Sec 'l Exp Chemrstry/SAz18 For Examine/s Use [Turn over

6 (c) The following diagram shows the substances remaining in the conical flask after the reaction. magnes!um chloride solution magnesium Describe how a pure and dry sample of magnesium chloride can be obtained t2l oo Sec 1 Exp Chemistry/SAz18 For Examine/s Use

7 2 The diagram below shows a separation technique used by a student to obtain pure water from seawater. condenser thermometer A seawaler boiling chips pure water (a) State the separation technique used. t1l (b) State and explain how the student can tell if the water collected is pure during the experiment. l2l (c) (i) Name process occurring at A and B. A, l2t B A A 2 I Sec 1 Exp Chemistry/SAzl8 [Turn Over Examinefs Use

I (ii) Draw the arrangement of water particles before and after process A in the boxes provided below. before after (iii) Using Kinetic Particle Theory, describe the change in movement and arrangement of the water particles in process B. t2) t3l movement: ..... arrangement. Sec 1 Ep Chemistry/SA2/.j 8 Examinels Use

I 3 The following excerpt is taken from a cookbook on how to prepare apple flavoured Konnyaku Jelly. (a) ldentify the solute and solvent in Step 3 used to form the red liquid. solute solvent. (b) Why was the mixture brought to a boil? t2l t1l 1 . Mix sugar and Konnyaku powder in a small bowl. 2. Pour apple juice in a saucepan and turn on the heat. 3. Slowly add in the sugar and Konnyaku powder mixture into the apple juice. 4. Bring it to a boil and continue to boil for another 5 minutes. 5. The resultant red liquid was poured into the moulds and chilled. Sec 1 Exp Chemrslry/SA2/18 [Turn Over Examine/s Use

10 (c) rock sugar fine sugar A_student wanted to compare how the different types of sugar would affect. the time taken to prepare the jelly. State the hypotheiis of the experiment and outline how the student can check if tire hypothesis is true. hypothesis: procedure: ..... t3l Sec 1 Exp Chemistry/SA2^8 Examine/s Use L-