Chapter 1 Practice Paper: The Scientific Endeavour — mark scheme
Secondary 1 · Lower Secondary Science (G2 / G3)
Mark scheme
The Scientific Endeavour
Chapter 1 Practice Paper · Maximum mark: 30
Notes for markers
- Award one mark for each point marked [1], up to the marks shown for the part.
- Accept answers worded differently that show the same understanding.
- Units are required where the answer line shows one. ecf: allow an error carried forward.
Section A: Multiple-choice questions[10 marks]
| Question | Answer | |
|---|---|---|
| 1 | BTurning the collar opens or closes the air hole. | 1 |
| 2 | BA millimetre ruler reads to the nearest 0.1 cm (1 mm), so the length is given to one decimal place in cm. | 1 |
| 3 | AA flame means flammable. A flame over a circle means oxidising. | 1 |
| 4 | DThe kelvin is the SI unit. Laboratory thermometers are usually marked in °C. | 1 |
| 5 | DHot liquid can spurt out of the tube, so it must point away from everyone. | 1 |
| 6 | A1 kg = 1000 g, so 0.25 kg = 0.25 × 1000 = 250 g. | 1 |
| 7 | CThe gas burns inside the barrel during a strike-back, so the barrel heats up very quickly. | 1 |
| 8 | AReading a scale from an angle makes the mark appear to be in the wrong place. | 1 |
| 9 | CArea is the independent variable and the time is the dependent variable; mass and drop height are controlled. | 1 |
| 10 | CHonest recording and reporting of all results is integrity. | 1 |
Section B: Structured questions[20 marks]
| Question | Answer and marking points | Marks |
|---|---|---|
| 1(a) | 42 cm³
Accept 42.0 cm³. Reject a reading taken from the top of the meniscus, or no unit. | 1 |
| 1(b) | Eye level with the bottom of the meniscus [1] Both ideas are needed for the mark: eye level, and the bottom (not the top) of the meniscus. | 1 |
| 1(c) | 47 − 42 = 5 cm³
Allow error carried forward from (a). | 2 |
| 1(d) | So that no water splashes out (and the glass does not crack), which would make the reading too low.
| 1 |
| Total for Question 1 | 5 | |
| 2(a) | Mass of salt (added) [1] Accept “amount of salt”. Reject “salt” alone: the variable is how much salt is added. | 1 |
| 2(b) | The boiling point of the water.
| 1 |
| 2(c) | Any two: the volume of water (100 cm³); the type of salt; the type of container; the way the temperature is measured.
Do not accept the mass of salt or the boiling point. | 2 |
| 2(d) | To check that the results are consistent and to calculate an average, so the results are more reliable. Repeating also shows up any anomalous result.
| 2 |
| Total for Question 2 | 6 | |
| 3(a) | The luminous (yellow) flame. It is cooler, because burning is incomplete, and it leaves black soot on the glassware.
| 2 |
| 3(b) | A blue, steady (non-luminous) flame with an inner blue cone. It is much hotter than the luminous flame.
| 2 |
| 3(c) | Turn off the gas tap immediately.
Do not accept “close the air hole” or “touch the collar”. | 1 |
| Total for Question 3 | 5 | |
| 4(a) | Flame: the liquid is flammable — it catches fire easily. Dripping liquid: it is corrosive — it destroys skin and attacks metals.
| 2 |
| 4(b) | Any two: keep it away from flames and heat; wear safety goggles and gloves; use only small amounts and close the bottle after use; report any spill to the teacher.
| 2 |
| Total for Question 4 | 4 |
— End of mark scheme —