Check your understanding 1. Explain why is it important to put a lid on the beaker, especially if the sample is left for a long time.
[2 marks]
......................................................................................................................................................... ......................................................................................................................................................... ......................................................................................................................................................... 2. Describe how the method could be changed to improve the accuracy of this experiment. [2 marks] ......................................................................................................................................................... ......................................................................................................................................................... ......................................................................................................................................................... 3. Osmosis occurs when there is a concentration gradient. Use your graph to estimate the concentration of the solution inside the potato cells.
[1 mark]
.........................................................................................................................................................
Exam-style questions 1. A student investigates the effect of different salt solutions on potato tissue. The results are shown in Table 2. Table 2 Concentration of salt solution in M
Starting mass in g
Final mass in g
Change of mass in g
Percentage (%) change in mass
0.0
1.40
1.62
0.22
15.7
0.2
1.45
1.61
0.16
11.0
0.4
1.40
1.46
0.06
0.6
1.44
1.39
–0.05
–3.5
0.8
1.32
1.22
0.10
–7.6
a. Calculate the percentage change in mass for 0.4 M salt solution.
[2 marks]
......................................................................................................................................................... ......................................................................................................................................................... Percentage change in mass ................................................%
AQA GCSE (9–1) Combined Science: Trilogy Required Practicals Lab Book
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