ACSI 2020 Y6 Prelim Paper 3_QP

Anglo-Chinese School (Independent) YEAR 6 PRELIMINARY EXAMINATION 2020 INTERNATIONAL BACCALAUREATE DIPLOMA PROGRAMME CHEMISTRY HIGHER LEVEL Paper 3 Tuesday 15 September 2020 1 hours 15 minutes INSTRUCTIONS TO CANDIDATES • Write your candidate number in the box above. • Do not open this examination paper until instructed to do so. • Answer all questions • A calculator is required for this paper. • A copy of the Chemistry Data Booklet is required for this paper. • Write your answers in the boxes provided. • The maximum marks for this examination paper is 45 marks. ________________________________________________________________________ This question paper consists of 14 printed pages including this cover page. For examiner’s use Section A Qn 1 /7 Qn 2 /8 Section B Qn 3 /6 Qn 4 /6 Qn 5 /8 Qn 6 /10 Total /45 Candidate Number Candidate Full Name

2 Section A Answer all questions. Answers must be written in the answer boxes provided. 1. "Lethal Dose", LD, is a means of measuring toxicity. LD50 is the amount of a material which causes the death of 50% of a group of test animals. Its value is expressed as the mass of a chemical administered per kg body mass of a test animal. "Lethal Concentration", LC, is another means of measuring toxicity. The value of LC 50 is the concentration of a chemical in the air that kills 50% of the test animals during the observation period. The table below shows the values for the LD50 and LC50 along with the toxicity ratings. Toxicity rating Commonly used term LD50: Oral (mg kg–1) LC50: Inhalation (ppm) 1 Extremely Toxic 1 or less 10 or less 2 Highly Toxic 1 – 50 10 – 100 3 Moderately Toxic 50 – 500 100 – 1000 4 Slightly Toxic 500 – 5000 1000 – 10 000 5 Practically Non-toxic 5000 – 15 000 10 000 – 100 000 6 Relatively Harmless 15 000 or more 100 000 or more (a) 9.90 × 10–4 mol of a toxic compound, C 4H5NO, was found to cause death in 50% of test animals weighing 1 kg. Calculate the LD50 of the compound and state its toxicity rating. [2] ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... (This question conti