2022 SCGS Chem Prelims P1

CANDIDATE NAME CLASS 4 REGISTER NUMBER CENTRE NUMBER INDEX NUMBER Chemistry Paper 1 Theory Additional Materials: Multiple Choice Answer Sheet 6092/01 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction tape/fluid. Write your name, class and index number on the Question Paper and Answer Sheet in the spaces provided. There are forty questions in this paper. Answer all questions. For each question, there are four possible answers, A, B, C, D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. A copy of the Periodic Table is printed on page 15. The use of an approved scientific calculator is expected, where appropriate. This question paper consists of 15 printed pages and 1 blank page. SINGAPORE CHINESE GIRLS’ SCHOOL Preliminary Examination Secondary Four Wednesday 31 August 2022 ���

2 1. A gas Y, is less dense than air, very soluble in water and is alkaline. Which method is used to collect a dry sample of the gas? 2. The following measurements are made on a sample pure water: its boiling point, its freezing point, and its pH. Sodium chloride is now dissolved in the water and the measurements repeated. How do the measurements change? boiling point freezing point pH A higher lower no change B higher higher increases C lower higher no change D lower lower decreases concentrated sulfuric acid ���

3 4. A particle contains 31 protons, 40 neutrons and 28 electrons. Which symbol is correct for this particle? A 𝑁𝑁𝑁𝑁3+ 28 59 B 𝐺𝐺𝐺𝐺3+ 31 71 C 𝐺𝐺𝐺𝐺31 70 D 𝑁𝑁𝑁𝑁3− 28 59 5. How many electrons in total are shared between the atoms in a molecule of ethene, C2H4, and in a molecule of water, H2O? ethene water A 6 2 B 10 4 C 12 4 D 14 8 3. The apparatus can be used to show the diffusion of gases. Two beakers containing gas P were placed over two porous pots containing gases Q and R respectively. The results are shown below. What is the correct order of the relative molecular mass of gases P, Q and R? Lowest Mr Highest Mr A R P Q B R Q P C Q P R D P Q R beaker beaker ���

4 6. Which element forms a positive ion with the same electronic configuration as an atom of neon? A chlorine B magnesium C lithium D oxygen 7. X, Y and Z are 3 different elements in the Periodic Table. The “dot and cross” diagram of the compound formed from X, Y and Z is shown below. Only the valence electrons are sho