2024 TMJC Prelim H2 Bio Paper 4 (A)

1 CANDIDATE NAME CIVICS GROUP _______________________________________________________________________________ H2 BIOLOGY 9744/04 Practical Paper 22 Aug 2024 2 hours 30 minutes Candidates answer on the Question Paper. _______________________________________________________________________________ READ THESE INSTRUCTIONS FIRST Do not open this booklet until you are told to do so. Write your name, civics group and index number on all the work you hand in. Give details of the practical shift and laboratory, where appropriate, in the boxes provided. Write in dark blue or black pen. You may use an HB pencil for any diagrams and graphs. Do not use staples, paper clips, glue or correction fluid/tape. Answer all questions in the spaces provided on the Question Paper. The use of scientific calculator is expected, where appropriate. You may lose marks if you do not show your working or if you do not use appropriate units. At the end of the practice, 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 18 printed pages and 2 blank pages. Shift Laboratory For examiner’s Use 1 / 22 2 / 16 3 / 17 Total / 55 TAMPINES MERIDIAN JUNIOR COLLEGE JC2 PRELIMINARY EXAMINATION Suggested Answers

2 Answer all questions. 1 Agar stained with universal indicator can be used to investigate diffusion. When hydrochloric acid diffuses into the agar it changes the colour from grey to pink. You will investigate the diffusion of different concentrations of hydrochloric acid in agar. You are provided with the materials shown in Table 1.1. Table 1.1 labelled contents hazard volume / cm3 H1 2.0 mol dm-3 hydrochloric acid irritant 20 W distilled water None 30 - 2 Petri dishes containing agar - - sheet T sheet T - - If H1 comes into contact with your skin, wash off immediately with cold water. It is recommended that you wear suitable eye protection. You will need to: • prepare different concentrations of hydrochloric acid, H1 − H4 • measure the diffusion distance for each concentration of hydrochloric acid and for an unknown concentration of hydrochloric acid, U. You will need to carry out a serial dilution of the 2.0 mol dm -3 hydrochloric acid, H1, to reduce the concentration by half between each successive dilution. You will need to prepare three concentrations of hydrochloric acid , H2, H3 and H4, in addition to 2.0 mol dm-3 hydrochloric acid, H1. After the serial dilution is completed, you will need to have 5 cm 3 of each concentration available to use.

3 (a) (i) Complete the table below to show how you will prepare your serial dilution. [3] Solution Concentration of hydrochloric acid / mol dm-3 Solution to be diluted Volume of solution to be diluted /cm3 Volume of water /cm3 H1 2.0 - - - H2 1.0 H1 5.0 5.0 H3 0.5