HCI_H1 Chem Prelim P 1

HWA CHONG INSTITUTION C2 PRELIMINARY EXAMINATIONS H1 CHEMISTRY 8872 PAPER 1 16 September 2008 50 min Do not open this booklet until you are told to do so. INSTRUCTIONS TO CANDIDATES 1. Check that there are 9 printed pages in this question booklet. 2. There are thirty questions in 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 Optical Mark Sheet provided. 3. Fill in your particulars on the optical mark sheet. Enter your NRIC number or FIN number and shade accordingly. 4. After the examination, you are required to submit only the optical mark sheet. INFORMATION FOR CANDIDATES Each correct answer will score one mark. Marks will not be deducted for wrong answers. A Data Booklet is provided. You may use a calculator. Any rough working should be done in this booklet. This question booklet consists of 9 printed pages.

SECTION A For each question, there are four possible answers, A, B, C, and D . Choose the one you consider to be correct. 1 A giant molecule contains a large amount of carbon of isotopes 12C and 13C. It was found that the relative atomic mass of carbon in the molecule is 12.20. What is the ratio of 12C to 13C in the molecule? A 4:1 B 3:1 C 3:4 D 1:4 2 Oxides of nitrogen are pollutant gases which are emitted from car exhausts. When a car travels one kilometer in urban traffic, it releases 0.23 g of an oxide of nitrogen NxOy, which occupies 120 cm3 under room conditions. What are the values of x and y? A x = 1, y = 1 B x = 1, y = 2 C x = 2, y = 1 D x = 2, y = 4 3 The redox reaction between hydrogen sulphide, H 2S, and sulphur dioxide, SO 2, gives elemental sulphur as the only sulphur-containing product. How many moles of sulphur dioxide react with one mole of hydrogen sulphide? A 3 1 B 2 1 C 3 2 D 1 4 10 cm 3 of 0.2 mol dm -3 K 2XO4 will just react with 40 cm 3 of 0.1 mol dm -3 iron(II) sulphate solution. If Fe2+ is oxidized to Fe3+ by K2XO4, what is the final oxidation state of X? A +2 B +3 C +4 D +5 5 Which of the following particles would have a half-filled set of p orbitals on losing an electron? A Si− B P C PP − D S+ 6 Which of the following molecules does not have a permanent dipole? A C2Cl4 B CF2Cl2 C CHCl3 D CF2CCl2 2008 HCI H1 Chemistry Preliminary Examination / Paper 1 2

7 Which of the following statements about covalent and/or ionic compounds is correct? A A covalent compound cannot be an electrolyte. B Compared to ionic compounds, covalent compounds are generally more soluble in polar solvents. C A covalent compound that contains both hydrogen and