Cambridge International Examinations Cambridge International Advanced Subsidiary and Advanced Level *8488148240* CHEMISTRY (11 Elective) 9701/21 AS Level Structured Questions 40 minutes Candidates answer on the Question Paper. Additional Materials: READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name 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 staples, paper clips, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. 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. This document consists of 4 printed pages with a data booklet IB17 03_9701_42/6RP © UCLES 2021 [Turn over Answer all the questions in the spaces provided. 1. Mass spectrometry is an analytical technique that can be used to deduce the molecular formula of an unknown compound or isotopes. A diagram of a mass spectrometer is shown in figure 2.1. Explain the process in mass spectrometer using the term “VIADD.” Show the reaction or process in each step. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... [5] 2. Define the term isotopes ....................................................................................................................................... [1] 3. Define the term relative atomic mass of Neon ....................................................................................................................................... [1] -23 4. The mass of one atom of Ne is 3.32 x 10 gram. -23 The mass of one atom of C-12 is 1.992 x 10 gram. 23 Avogadro Constant is 6.02 x 10 atom/mol. Use your definition in question 3, prove that the relative atomic mass of Neon is 20.0. Show your workings ................................................................................................................................................ [1] 5. A pure sample of element X is analysed using mass spectrometry. The mass spectrum obtained is shown. Show how you would determine the identity of the element X. ........................................................................................................................................ [2] 13 14 15 6. Nitrogen has three stable isotopes, N, N and N. All three isotopes are present in a sample of nitrogen gas, N2, which was analysed using a mass spectrometer. + Explain and prove that there are five peaks associated with the N2 ion. ........................................................................................................................................ [2] 7. A compound Y has a molecular ion (M+) at m/e value of 120, and relative abundance 23% and M+1 peak at m/e 121 with a relative abundance 2%. How many carbon atoms are in a molecule of Y? Show your working. .............................................................................................................................................. [1] 8. An unknown compound Z was isolated and testes using mass spectrometer. Compound Z contains carbon, hydrogen, and oxygen. Show how you would approach the problem and how to obtain information from the spectrum of compound Z. Write any information you can obtain from the spectrum. The [M+1] peak has been removed from the spectrum. ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... ....................................................................................................................................... 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