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P3 General Studies: Dissolving and Separation (Paper 1 (basics))
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P3 General Studies: Dissolving and Separation (Paper 1 (basics))
Paper one trains the basic judgement: dissolving is spreading out, not disappearing; the total mass stays the same; sand does not dissolve; filtration cannot split sugar from water, plus simple percentage calculations.
Direct answers For each item ask first where the particles are, then decide whether it dissolves or not, and only then do the calculation.
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 |
| Suggested time | 20 |
| Difficulty mix | Foundation 3 · Intermediate 3 · Challenge 3 · Error redo 1 |
| Chapter | Chapter: P3 General Studies: Dissolving and Separation |
| Level | parts of a closed circuit, conductors against insulators, series against parallel, adding up battery voltage, and electrical safety |
02 Questions (10 items)
- FoundationA spoon of sugar is stirred into water and disappears. What is this process called?
- FoundationDoes the total mass change before and after the sugar dissolves?
- FoundationIf sand is stirred into water, does it dissolve?
- Intermediate10 g of salt is fully dissolved in 50 g of water. What is the total mass of the salt solution?
- IntermediateA cup of sugar solution has a mass of 120 g and contains 20 g of sugar. What is the mass of the water?
- IntermediateCan filter paper separate the sugar from the water in a sugar solution?
- ChallengeGrinding a sugar cube into powder makes it dissolve faster. What has been changed?
- ChallengeAt 20 degrees Celsius, 100 g of water dissolves at most 36 g of salt. If 40 g of salt is added to 100 g of water, how much salt stays undissolved?
- ChallengeA 200 g salt solution contains 8 g of salt. What percentage of the solution is salt?
- Error redoA classmate says the sugar disappears after dissolving, so the mass must decrease. What is wrong?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | Dissolving. | The sugar particles spread through the water; they are too small to be seen but they are still there. |
| 2 | No, the total mass stays the same. | Dissolving only spreads the particles out; nothing disappears, so the mass does not change. |
| 3 | No, sand does not dissolve in water. | The sand particles do not spread through the water; they settle at the bottom. |
| 4 | 60 g | Fifty plus ten equals sixty; dissolving does not change the total mass. |
| 5 | 100 g | One hundred and twenty minus twenty equals one hundred. |
| 6 | No, the sugar passes through the filter paper with the water. | The sugar is dissolved, so its particles are smaller than the holes in the filter paper. |
| 7 | The surface area of the sugar in contact with the water has increased. | A larger surface area lets the water reach more of the sugar, so it dissolves faster. |
| 8 | 4 g | Only 36 g can dissolve, and forty minus thirty-six leaves four grams at the bottom. |
| 9 | 4.0 percent | Eight divided by two hundred times one hundred gives 4.0 percent. |
| 10 | The sugar has not disappeared; it is spread out as tiny particles and the total mass is unchanged. | The particles are still in the cup, so a balance shows exactly the same mass. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
After paper one, take paper two and sort out series against parallel in one pass.Tutor Registration →
Questions and answers are written originally by the TutorZone team and are not taken from any school, publisher or examination authority paper. Every value is checked by computer.