NJC 2024 Time Practice 2 Answer Booklet

1 NJC SH2 Timed Practice 9729/01/24 [Turn over NATIONAL JUNIOR COLLEGE SH2 TIMED PRACTICE Higher 2 CANDIDATE NAME SUBJECT CLASS REGISTRATION NUMBER CHEMISTRY Paper 1 Multiple Choice Additional Materials: Optical Answer Sheet Data Booklet 9729/01 27 June 2024 1 hour READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name, subject class and registration number on the Answer Sheet in the spaces provided unless this has been done for you. There are thirty 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 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. The use of an approved scientific calculator is expected, where appropriate. A Data Booklet is provided. Instructions on how to fill in the Optical Mark Sheet Shade the index number in a 5 digit format on the optical mark sheet: 2nd digit and the last 4 digits of the Registration Number. Example: Student Examples of Registration No. Shade: 2305648 35648 This document consists of 12 printed pages.

2 NJC SH2 Timed Practice 9729/01/24 1 2 3 4 6 7 8 9 10 A C A D B C D A D 11 12 13 14 15 16 17 18 19 20 B B D B C C C C A B 21 22 23 25 27 28 29 30 D C C C D D B D 1 Which statement about one mole of a metal is always correct? A It contains the same number of atoms as 0.5 mol of hydrogen gas. B It contains the same number of atoms as 1 12 mol of 12C. C It has the same mass as 1 mol of hydrogen atoms. D It can be oxidized by a reaction with an acid. Ans: A Option A is correct 1 mol of M = 6.02 × 1023 atom ½ mol of H2 = 1 mol of H atom = 6.02 × 1023 atom Option B is wrong 1 mol of M = 6.02 × 1023 atom 1 12 mol of 12C = 1 12 × 6.02 × 1023 Option C is wrong Mass of 1 mol of H atom = 1 g Mass of 1 mol of M = 1 × Ar of metal Option D is wrong Not all metal can be oxidized by an acid (H+) Cu2+ + 2e Cu E = +0.34V 2H+ + 2e H2 E = 0.00V Eꝋcell = Eꝋ[R] – Eꝋ[O] Eꝋcell = Eꝋ(H+/H2)– Eꝋ(Cu2+/Cu) = 0.00 – (+0.34) = – 0.34 V Reaction between H+ and Cu is not feasible.

3 NJC SH2 Timed Practice 9729/01/24 [Turn over 2 10 cm3 of a gaseous hydrocarbon was reacted with an excess of oxygen. A contraction of 30 cm3 occurred. On treating the cooled resulting mixture with excess barium hydroxide, a further contraction of 40 cm3 occurred. All volumes were measured at room te