CHEM1011 · Chemistry 1a
Laboratory Skills, Safety and Reports
The weekly laboratory program carries 20% of the course mark and two of the three pass hurdles — you must attend at least six lab classes and be awarded all core laboratory skills. This chapter covers the skills-based marking scheme, the pre-lab quizzes that scale the non-core mark, the safety and PPE requirements, and how to record and report data (e.g. preparing a standard solution) to the required significant figures and coversheet standard.
What this chapter covers
- 01The 20% laboratory component and its two hurdles: attend ≥ 6 lab classes and be awarded all core lab skills
- 02The skills-based mark: core skills = 10/20; non-core marks scaled by your pre-lab quiz average
- 03The lab manual's core-skill list in full — safety, ethics and fume-cupboard inductions, chemical and analytical glassware, weighing, heating materials, titration, scientific graphing — every one must be awarded
- 04Pre-lab quizzes: complete before each session; they scale the non-core portion of the mark
- 05Safety and PPE: lab coat, safety eyewear, enclosed footwear; following the evacuation/safety notes
- 06Recording observations to the correct significant figures and the precision of the instrument
- 07Preparing and standardising solutions (n = cV, mass by difference) as a representative report task
- 08Writing the individual report to the coversheet standard, honestly and within the academic-integrity policy
Mass of solid needed to prepare a standard solution
- +1Find the moles required: n = c·V = 0.1000 mol L⁻¹ × 0.2500 L = 0.02500 mol (convert 250.0 mL to 0.2500 L first).
- +1Confirm the molar mass: M(Na₂CO₃) = 2(22.99) + 12.01 + 3(16.00) = 45.98 + 12.01 + 48.00 = 105.99 g mol⁻¹.
- +1Mass required: m = n·M = 0.02500 mol × 105.99 g mol⁻¹ = 2.650 g.
- +1Report to the significant figures set by the data (4 s.f.): 2.650 g. In practice weigh by difference and record the actual mass to the balance's precision, then use that exact mass to compute the true concentration.
Key terms
- Core laboratory skill
- A technique you must be awarded to pass the course (part of the lab hurdle), such as correct use of volumetric glassware or weighing by difference; core skills are worth 10/20 of the lab mark.
- Weighing by difference
- Massing a container before and after dispensing a solid and taking the difference, which cancels the container mass and gives an accurate sample mass to the balance's precision.
- Volumetric glassware
- Precision apparatus (pipette, burette, volumetric flask) calibrated to deliver or contain an exact volume; essential for preparing and standardising solutions accurately.
- Standard solution
- A solution of accurately known concentration, prepared from a known mass of solute in a known volume (n = cV) or standardised against a primary standard.
- Pre-lab quiz
- An online quiz completed before each laboratory session; your average pre-lab performance scales the non-core portion of the 20% laboratory mark.
- Personal protective equipment (PPE)
- The lab coat, safety eyewear and enclosed footwear required in the teaching laboratory; wearing correct PPE is part of the safety expectations for attendance.
Laboratory Skills, Safety and Reports FAQ
How is the 20% laboratory mark actually built?
It is skills-based rather than report-score-based. The core skills are worth 10/20 and you must be awarded all of them to pass — they are a hurdle, not just marks. The remaining non-core portion is then scaled by your pre-lab quiz average, so keeping up with the pre-lab quizzes directly protects your lab mark. On top of the marks, you must attend at least six lab classes to satisfy the attendance hurdle.
What happens if I miss labs or don't complete the pre-lab quizzes?
Missing labs risks the attendance hurdle — you need at least six classes — and not being awarded a core skill risks the core-skills hurdle, either of which can stop you passing regardless of your written marks. Skipping pre-lab quizzes lowers the average that scales your non-core lab mark. Because the labs carry two of the three pass hurdles, treat attendance and the pre-lab quizzes as non-negotiable and confirm the exact rules on Moodle.
How precisely should I record and report laboratory data?
Record every measurement to the precision the instrument supports — a balance to its last stable digit, volumetric glassware to its calibrated tolerance — and keep unrounded values through the calculation, rounding once at the end. Your reported significant figures should reflect the least-precise measured quantity. Honest recording of what you actually observed (not an idealised value) is also an academic-integrity requirement.
Can Sia help me prepare for labs and reports?
Yes. Sia can walk the calculations behind a lab task — moles for a standard solution, dilution, back-calculating a true concentration from an actual weighed mass — and help you apply significant-figure and unit conventions in a report. It explains the method and checks your reasoning; it does not complete your assessed report for you, and the UNSW academic-integrity policy applies to laboratory work as much as to exams.
Exam move
Protect the lab hurdles first, because they can end your course independently of your marks: plan to attend at least six classes and make sure you are awarded every core skill (volumetric technique and weighing by difference are the usual ones). Do the pre-lab quiz before every session — it is quick marks and it scales your non-core lab score — and read the experiment beforehand so bench time is spent on technique, not catching up. Practise the recurring calculations that reports rely on (n = cV for a standard solution, dilution, back-calculating the true concentration from the mass you actually weighed) and apply the significant-figure rules from Chapter 1 honestly to your own data. Follow the PPE and safety requirements as a matter of course. Write reports to the coversheet standard, recording what you genuinely observed — accurate, honest data is both good science and an academic-integrity expectation. When a lab calculation is unclear, ask Sia to work a parallel example.
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