Recover both an insoluble solid and a dissolved solid from a mixture.
| English | Chinese |
|---|---|
| residue | 滤渣 |
| filtrate | 滤液 |
| saturated | 饱和的 |
| crystallisation | 结晶 |
Try each question before opening its hint or answer. Use paper for calculations and diagrams.
A mixture contains gravel and sugar solution. Which step should come first if you want to collect sugar crystals?
Remove the insoluble material before concentrating the solution.
Filter first to remove the gravel. The sugar remains dissolved in the filtrate and can then be obtained by crystallisation.
Explain why filtration separates sand from water but cannot separate copper(II) sulfate from its solution.
Ask whether the solid is dissolved or suspended.
Sand is insoluble and stays on the filter paper. Dissolved copper(II) sulfate passes through in the filtrate.
Describe how to obtain dry copper(II) sulfate crystals from its aqueous solution.
Remove only some solvent before cooling; then separate and dry the crystals.
Gently evaporate some water to the crystallisation point. Cool. Filter the crystals, wash with a little cold distilled water and dry between filter papers.
Use Lesson 2 in your worksheet for written practice. Your teacher will discuss those answers in class.