Visking tubing can be used to investigate the properties of cell membranes. A student carried out an experiment to investigate osmosis using Visking tubing. An outline of the investigation is shown in Fig. 3.1. [Figure 3.1]. Six pieces of Visking tubing were filled with 10cm³ of different concentrations of sucrose solution: 0.0, 0.4, 0.8, 1.2, 1.6 and 2.0moldm⁻³. The height of the meniscus of each solution in the Visking tubing was measured. The pieces of Visking tubing were put into test-tubes containing 15cm³ of 0.9moldm⁻³ sucrose solution. After 20 minutes, the pieces of Visking tubing were removed from the test-tubes and the height of the meniscus in each was measured. The results are shown in Table 3.1. Table 3.1: concentration of sucrose solution inside Visking tubing /moldm⁻³ and difference in height of meniscus after 20 minutes/mm. Data: 0.0 / -12, 0.4 / -4, 0.8 / -2, 1.2 / +1, 1.6 / +6, 2.0 / +11.
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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