A student adds crystals of substance P to distilled water. Some of the crystals remain undissolved.
The student separates the clear solution from the undissolved residue. The residue is washed and dried before it is tested.
| Sample tested | Conducts electricity? |
|---|---|
| Distilled water before P is added | No |
| Mixture of solution and undissolved crystals | Yes |
| Clear solution after the undissolved crystals are removed | Yes |
| Washed and dried undissolved residue | No |
The student claims, “The mixture conducts electricity because charged particles move through the undissolved crystals.”
State the type of structure in substance P.
Evaluate the student's claim. Use all the results in the table in your answer.
122 exam-style questions on OCR GCSE Chemistry 2.3 Properties of materials, covering 2.3.1 Carbon bonding and the variety of organic compounds, 2.3.2 Diamond, graphite, fullerenes and graphene, 2.3.3 Bond strength, changes of state and predicting states, 2.3.4 Bulk properties and types of bonding, and 2.3.5 Nanoparticles: scale, surface area, uses and risks. Each one has a worked solution and a mark scheme showing where the marks go.