A student is separating some mixtures. She wants to obtain pure water from a sugar solution. She filters the mixture.
Her method does not work.
Explain why her method does not work and describe the method she should use.
The student wants to separate a mixture of two miscible liquids.
The liquids are:
| Liquid | Boiling point (∘C^{\circ}\text{C}∘C) |
|---|---|
| Propanone | 56 |
| Water | 100 |
Which separation technique should she use?
Explain how the method works.
The student separates two solid substances A and B. She wants to check that they are pure.
What is meant by a pure substance in chemistry?
The student measures the melting points of four samples of solid B.
Look at her results:
| Sample | Melting point (∘C^{\circ}\text{C}∘C) |
|---|---|
| 1 | 129–133 |
| 2 | 134 |
| 3 | 130 |
| 4 | 135–137 |
She knows that a pure sample of solid B has a melting point of 135∘C135^{\circ}\text{C}135∘C.
She concludes that sample 4 is the purest sample of solid B.
Do the results support her conclusion?
Explain your answer using evidence from the table.