AS 92021 annotated exemplars

An annotated exemplar is a sample of student evidence, with a commentary, to explain key aspects of the standard. It assists teachers to make assessment judgements at the grade.

Download all exemplars and commentary [PDF, 2.7 MB]

NCEA Chemistry and Biology resources (external link)

For Achieved, the student needs to demonstrate understanding of chemical reactions in context.

This involves describing the reactants and products for a range of chemical reaction types using equations, with reference to conservation of mass. It also involves linking each chemical reaction to a context, using predictable patterns or observations. A range of chemical reactions means at least three different reaction types are required, as outlined in Explanatory Note 2 of the standard.

This student has described the reactants and products using equations selected from the Resource Sheet and referred to conservation of mass by stating that matter is not created nor destroyed. The student has also linked the reaction to the context of antacids using the predictable pattern through the evidence. Similar evidence for another two different reaction types is required for an overall grade of Achieved.

For Merit, the student could explain the relationship between the reactants and the products in the reaction and use observations from the context of antacids to link the chemical reaction to the context.

For Merit, the student needs to explain chemical reactions in context.

This involves explaining the relationship between the reactants and products for the range of chemical reactions using equations, with reference to conservation of mass. It also involves explaining how each chemical reaction links to a context, using predictable patterns and observations. 

This student has explained the relationship by showing how the elements in the reactants rearrange into the products supported by the balanced chemical equation and shows how the quantity of each element is the same in the reactants and products. The student has also used both observations (found in questions 1c, 2a, and 3) and the predictable pattern (in question 1b) to explain how the reaction links to the context of sparklers. Similar evidence for another two different reaction types is required for an overall grade of Merit.

For Excellence, the student could discuss an implication of conservation of mass for the reaction in the context of sparklers.

For Excellence, the student needs to interpret chemical reactions in context.

This involves discussing the implications of conservation of mass in the context of each chemical reaction, with reference to predictable patterns, observations, and equations.

This student has discussed an implication of conservation of mass related to the combustion context of cooking with natural gas. The student used conservation of mass to discuss the observation of soot forming on the outside of the pot when there was a decrease in the amount of oxygen available to react with methane. This is linked to predictable patterns, observations, and equations (both complete and incomplete combustion). Similar evidence for two other different reaction types is required for an overall grade of Excellence.