What this standard actually asks for

How this standard is assessed

• AS91389 is internally assessed as a research report, usually written over two to three weeks from resources your teacher supplies.
• It has no fixed content. What is fixed is the structure of the argument you must produce.

The three verbs

Grade	Verb	What you must produce
Achieved	Account	An accurate description of the chemical processes, with formulae and balanced equations
Merit	Explain links	The chemistry connected to its consequences for people or the environment
Excellence	Evaluate	A judgement — the size of the impact, the issues arising, what is uncertain, and comparison between processes or responses

• The Excellence criterion names three ways to get there: elaborating on, comparing and contrasting, or analysing the links. Any one of them is enough, and choosing which suits your topic is worth thinking about before you write.

Equations are compulsory at every grade

• Explanatory Note 2 requires the account to be supported by the use of chemistry vocabulary, symbols, conventions, and equations — at Achieved.

• At Merit those elements must be integrated into the explanation, not appended to it.

• At Excellence the integration must be consistent throughout.

• "Integrated" means the equation is doing explanatory work in the sentence around it, not sitting in a box on its own. Compare:

  • Appended: "Carbon dioxide dissolves in seawater. The equation is CO₂ + H₂O ⇌ H₂CO₃."
  • Integrated: "Because dissolved CO₂ reacts with water to form carbonic acid, $\text{CO}_2(g) + \text{H}_2\text{O}(l) \rightleftharpoons \text{H}_2\text{CO}_3(aq)$, which then ionises to release H⁺, an increase in atmospheric CO₂ necessarily lowers the pH of the surface ocean."

The chain you are being assessed on

Every strong report in this standard has the same shape:

• The chemical process — what reacts with what, with equations.

• The consequence — what that process causes to happen in the world.

• The impact — who or what is affected, and how much.

• The response — what has been or could be done, and its own chemistry.

• The evaluation — how big, how certain, and how the options compare.

• Merit lives in the link between the first two. Excellence lives in the last one.

Choosing a context

A good choice for this standard has:

• Chemistry you can actually explain at Level 3 — equilibrium, acids and bases, redox, thermochemistry, organic.
• Equations you can write and balance.
• Documented consequences, preferably with numbers.
• A genuine trade-off or unresolved issue, which is what an evaluation needs.
• Ideally a New Zealand dimension, which makes the impact concrete.

Context	Chemistry it runs on	The issue to evaluate
Ocean acidification	carbonate equilibria, Le Châtelier, weak acids	shellfish and aquaculture vs global CO2 control
Nitrogen in freshwater	redox, the nitrogen cycle, the Haber process	food production vs water quality
Ozone depletion	catalytic cycles, bond energies, UV absorption	the Montreal Protocol's success vs its replacements
Acid rain	SO2/NOx oxidation, acid–base	emissions control cost vs ecosystem damage
Geothermal energy	dissolution, precipitation, H2S chemistry	renewable energy vs arsenic and silica discharge
Green hydrogen / ammonia	electrolysis, Haber–Bosch, thermochemistry	decarbonising fertiliser vs energy cost