SMSS Sec 3 pure chem paper 2 2024

This document consists of 15 printed pages. ST. MARGARET’S SCHOOL (SECONDARY) End-of-Year Examinations 2024 CANDIDATE NAME CLASS REGISTER NUMBER CHEMISTRY Paper 2 Theory Secondary 3 Express 6092/02 26 September 2024 2 hours Additional Materials: NIL READ THESE INSTRUCTIONS FIRST Write your name and register number on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams, graphs, tables or rough working. Do not use staples, paper clips, highlighter, glue or correction fluid. Answer all questions in the spaces 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. The use of an approved scientific calculator is expected, where appropriate. A copy of the Periodic Table is printed on page 15. For Examiner’s Use Total / 65 marks Paper 1 and 2:

2 SMS(S) 2024 Answer all the questions in this section in the spaces provided. The total mark for this section is 65. 1 Use only the substances below to answer the following questions. Each substance may be used once, more than once, or not at all. (a) Name one substance that has the same rate of diffusion as nitrogen gas. [1] (b) Name one substance which is a neutral oxide. [1] (c) Which two substances react to form a blue solution? [1] (d) Which two elements combine to form a solid that has a high melting point? [1] (e) Which two substances contain atoms arranged in a tetrahedral manner? [1] [Total: 5] lithium sulfuric acid carbon monoxide iodine copper(II) oxide water silicon dioxide methane bromine hydrochloric acid graphite silicon

3 SMS(S) 2024 2 A sample of black ink contains a mixture of red, blue and yellow dyes. A solvent mixture of ethanol and water can be used to separate the dyes in the black ink. The coloured dyes have different Rf values in solvents with different compositions of ethanol as shown in the graph in Fig 2.1. (a) Using information from the graph in Fig 2.1, explain why pure water would not be suitable for the separation of the black ink by using paper chromatography. [2] (b) A student carried out chromatography on the black ink using a certain mixture of ethanol and water as a solvent. The result showed only one spot on the chromatogram. From the graph in Fig 2 , state the percentages of ethanol and water in the solvent which the student used that resulted in only one spot. [1] Fig 2.1

4 SMS(S) 2024 (c) The black ink was separated using 80% of ethanol. What is the distance travelled by a spot of blue dye if the solvent front on the chromatogram is 10.0 cm? Show your working. [2]