Pupil sheet · Mixtures and separation
Mixtures and separation — return questions
Name ______________________ Date ____________
Use one to two weeks after the lessons. Keep the notes and the lesson closed.
1. Identify / Explain
Keep the lesson closed. A lab note says: ‘Solid benzoic acid dissolved completely in liquid ethanol.’ Identify the solvent and use the note to explain your choice.
2. Describe / Explain
A teacher removes all water from a solution. Its non-volatile solid stays chemically unchanged in the basin. No paper was used. Explain whether you can still call the solid residue.
3. Suggest / Explain
A lab note compares liquids for solids N and O. Neither solid changes chemically. A dissolves only O; B dissolves both; C dissolves neither. Paper retains undissolved N. Choose a liquid for dissolving and filtering. Describe each solid's destination.
4. Identify / Explain
A sealed sample contains only sugar and water. All the sugar has dissolved. Identify the solute and name both components still present. Explain why ‘no visible crystals’ doesn't mean ‘water only’.
5. Explain / Suggest
A sample began as water and insoluble grains. Some grains are visible in the receiver after attempted filtration. Explain what that shows and suggest two possible causes. Does it establish that the solid dissolved?
6. Explain
Bottle1 contains ethanol with iodine fully dissolved throughout. Bottle2 contains oil and water in separate layers. Classify each mixture and explain why. Bottle3 is clear but has no contents label. Can appearance tell you whether it's pure?
7. Describe / Explain
A note says intact paper retained insoluble J. The liquid that crossed it contained water and dissolved H. Describe the filtrate and explain why J isn't part of its stated composition.
8. Suggest / Describe / Explain
A dry powder contains A, B and C. Only A is attracted by the magnet, which is specified for dry-powder collection. B dissolves in water; C doesn't, and paper retains C. None reacts with water. B stays unchanged and non-volatile during approved water removal. Describe and justify a sequence to collect all three solids separately.