Paper 6 structured question: Osmosis
Paper 6Alternative to PracticalPractical6 marks
Method
Method for Investigating Osmosis in Potato Cylinders
1. Cut potato cylinders of equal size. 2. Measure and record the initial mass of each cylinder. 3. Place each cylinder in a different sucrose solution concentration (0%, 5%, 10%, 15%, 20%) for 30 minutes. 4. Remove cylinders, blot dry, and measure the final mass. 5. Calculate the percentage change in mass for each cylinder.
| Solution concentration (%) | Initial mass (g) | Final mass (g) | Percentage change in mass (%) |
|---|---|---|---|
| 0 | 2.00 | 2.20 | 10 |
| 5 | 2.00 | 2.10 | 5 |
| 10 | 2.00 | 2.00 | 0 |
| 15 | 2.00 | 1.90 | -5 |
| 20 | 2.00 | 1.80 | -10 |
- a[1]
Identify the independent variable in this investigation.
Aim for approximately 1 distinct marking point.
- b[2]
Describe how the percentage change in mass is calculated.
Aim for approximately 2 distinct marking points.
- c[3]
Explain why the potato cylinders lost mass in the 15% and 20% sucrose solutions.
Aim for approximately 3 distinct marking points.