2018 C1 Promotional Exam Paper 1

This question booklet consists of 12 printed pages. HWA CHONG INSTITUTION C1 Promotional Examination Higher 2 NAME CT GROUP 18S CHEMISTRY Paper 1 Multiple Choice Additional Materials: Multiple Choice Answer Sheet Data Booklet. 9729/01 2 October 2018 40 min READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Complete the information on the optical mark sheet (OMS) as shown below. There are twenty questions on this paper. Answer all questions. For each question, there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the OMS. 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. The use of an approved scientific calculator is expected, where appropriate.

2 2018 HCI C1 H2 Chemistry Promotional Exam / Paper 1 1 The graph shows the first ionisation energies of five consecutive elements in the Periodic Table. Which group does D belong to? A 2 B 14 C 15 D 18 2 Semiconductors are widely used in electronic devices. An element can be a semiconductor if it meets the following criteria: • One of its electronic levels is fully occupied (such as an s subshell) • The level immediately above this level is of only slightly higher energy, and is empty or partially filled (such as a p subshell) On this basis, which elements are expected to be semiconductors? 1 31Ga 2 34Se 3 55Cs A 1 only B 1 and 2 only C 2 and 3 only D 1, 2 and 3 ABCDE first IE / kJ mol–1

3 2018 HCI C1 H2 Chemistry Promotional Exam / Paper 1 3 In which pair does species I have a smaller bond angle than species II? I II A NO3– NO2– B ClF4– SF6 C XeF4 BrF5 D BrO3– ClO3– 4 Which pair of compounds is arranged in the correct order of relative boiling points? Lower boiling point Higher boiling point A B CH3CH2OH C CH3CH2OH D

4 2018 HCI C1 H2 Chemistry Promotional Exam / Paper 1 5 Carbon forms double bonds with each of the three elements oxygen, sulfur and selenium. In each case, the double bond is polar. In the linear molecules, carbon dioxide, carbonyl sulfide (COS) and carbonyl selenide (COSe), the polarities of these double bonds do not necessarily cancel. Overall polarity of molecule O=C=O 0 O=C=S 0.71 O=C=Se 0.73 Which factors could account for these observations? 1 The C=S bond is more polar than the C=Se bond. 2 The C=O bond is more polar than the C=S bond. 3 The C=Se bond is more polar than the C=O bond. A 1 only B 1 and 2 only C 1 and 3 only D 2 and 3 only

5 2018 HCI C1 H2 Chemistry Promotional Exam / Paper 1 7 The amount of urea present in urine can be determined by measuring the volume of gases liberated when urea is treated with excess nitrous acid. NH2CONH2 + 2HNO2 ® CO2 + 2N2 + 3H2O 0.150 g of urea was treated with excess nitrous acid