2023 EJC H3 Chemistry Prelim Key Answer

© EJC [Turn Over EUNOIA JUNIOR COLLEGE JC2 Preliminary Examination 2023 General Certificate of Education Advanced Level Higher 3 CANDIDATE NAME CIVICS GROUP 2 2 – INDEX NUMBER CHEMISTRY Paper 1 9813/01 22 September 2023 2 hours 30 minutes Candidates answer on Question Paper. Additional Materials: Data Booklet Insert READ THESE INSTRUCTIONS FIRST Write your name, civics group and registration number on all the work you hand in. Write in dark blue or black pen. You may use an HB pencil for any diagrams or graphs. Do not use staplers, paper clips, glue or correction fluid. Answer all questions in the spaces provided on the Question Paper. If additional space is required, you should use the pages at the end of this booklet. The question number must be clearly shown. Section A Answer all questions. Section B Answer two questions. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. For Examiner’s Use Section A 1 / 20 2 / 11 3 / 16 4 / 13 Section B 5 / 20 6 / 20 7 / 20 Total / 100 This document consists of 48 printed pages.

2 © EJC 9813/01/J2PE/23 Section A Answer all the questions in this section. 1 (a) Carbon dioxide is the primary but not the sole contributor to the carbon reserve in the atmosphere. (i) Name another greenhouse gas which contributes to the carbon reserve and state one source of this gas. [2] (ii) Assume that the carbon reserve in the atmosphere is fully in the form of CO 2, and that the composition of dry air by volume is 78.08% N 2, 20.95% O 2, 0.93% Ar and 0.04% CO 2. Use the data in Fig. 1.1 to estimate the mass of the Earth’s atmosphere, in kg. [2] ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ......