Paper 6 structured question: Osmosis
Paper 6Alternative to PracticalPractical3 marks
Method
Method for Osmosis Investigation
1. Cut equal lengths of dialysis tubing and soak in water to soften. 2. Tie one end of each tubing to form a bag. 3. Fill each bag with 10 cm³ of sugar solution at different concentrations (0%, 10%, 20%, 30%). 4. Tie the open end securely. 5. Blot dry and weigh each bag. 6. Place each bag in separate beakers containing 100 cm³ distilled water. 7. Leave for 30 minutes at room temperature. 8. Remove bags, blot dry, and weigh again. 9. Record the change in mass for each bag.
| Sugar concentration (%) | Initial mass (g) | Final mass (g) | Change in mass (g) |
|---|---|---|---|
| 0 | 5.0 | 5.5 | +0.5 |
| 10 | 5.1 | 5.4 | +0.3 |
| 20 | 5.0 | 5.0 | 0 |
| 30 | 5.2 | 5.0 | -0.2 |
- a[1]
Identify the independent variable in this investigation.
Aim for approximately 1 distinct marking point.
- b[2]
Describe how you would measure the dependent variable in this investigation.
Aim for approximately 2 distinct marking points.