# Marking Guide: Enthalpy Changes and Calorimetry

## Task

Students present a labelled model or report on enthalpy changes and calorimetry.

## Curriculum alignment

This task assesses student understanding of energy changes in chemical reactions, drawn from the following outcomes:

- 30-A1.1k: recall the application of Q = mcΔt to the analysis of heat transfer ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634))
- 30-A1.3k: define enthalpy and molar enthalpy for chemical reactions ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636))
- 30-A1.5k: use and interpret ΔH notation to communicate and calculate energy changes in chemical reactions ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638))
- 30-A1.6k: predict the enthalpy change for chemical equations using standard enthalpies of formation ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23639))
- 30-A1.7k: explain and use Hess' law to calculate energy changes for a net reaction from a series of reactions ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23640))
- 30-A1.8k: use calorimetry data to determine the enthalpy changes in chemical reactions ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23641))
- 30-A1.10k: classify chemical reactions as endothermic or exothermic, including photosynthesis, cellular respiration and hydrocarbon combustion ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23643))
- 30-A2.2k: explain the energy changes that occur during chemical reactions, referring to bonds breaking and forming and changes in potential and kinetic energy ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23652))
- 30-A2.3k: analyze and label energy diagrams of a chemical reaction, including reactants, products, enthalpy change and activation energy ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23653))

These outcomes fall under the general outcomes to determine and interpret energy changes in chemical reactions ([Topic](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23633)) and to explain and communicate energy changes in chemical reactions ([Topic](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23650)), within the Energy, Change and Systems unit ([Topic](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23632)).

## Rubric

| Criterion | Beginning | Developing | Proficient | Exemplary |
|---|---|---|---|---|
| Calorimetry and heat transfer calculations | Applies Q = mcΔt incorrectly or omits calorimetry data entirely ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23641)). | Applies Q = mcΔt with errors in variables or units; calorimetry data partially used ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23641)). | Applies Q = mcΔt correctly with proper units; calorimetry data used to determine enthalpy change ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23641)). | Applies Q = mcΔt with precision, justifies assumptions, and cross-checks calorimetry results against expected values ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23641)). |
| Enthalpy definitions and ΔH notation | Defines enthalpy incorrectly or omits ΔH notation ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638)). | Defines enthalpy or molar enthalpy with minor inaccuracies; ΔH notation used inconsistently ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638)). | Defines enthalpy and molar enthalpy accurately; ΔH notation used correctly to communicate energy changes ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638)). | Defines enthalpy and molar enthalpy with precision and applies ΔH notation fluently across multiple reaction contexts ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638)). |
| Hess' law and standard enthalpies of formation | Does not apply Hess' law or formation enthalpies, or applies them with major conceptual errors ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23639), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23640)). | Applies Hess' law or formation enthalpies with arithmetic or conceptual errors ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23639), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23640)). | Correctly predicts enthalpy change using standard enthalpies of formation and applies Hess' law to a series of reactions ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23639), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23640)). | Applies Hess' law and formation enthalpies accurately, explaining the reasoning behind combining reaction equations ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23639), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23640)). |
| Energy diagrams and classification of reactions | Labels energy diagrams incompletely; does not classify reactions as endothermic or exothermic ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23643), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23652), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23653)). | Labels most diagram components; classifies reactions with some errors; limited reference to bond breaking and forming ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23643), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23652), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23653)). | Labels reactants, products, enthalpy change and activation energy correctly; classifies reactions accurately, referencing bond and energy changes ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23643), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23652), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23653)). | Labels diagrams fully and accurately; explains classification with clear reference to bond breaking, bond forming, and potential and kinetic energy changes ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23643), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23652), [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23653)). |

## Scoring

Assign each criterion a level from Beginning (1) to Exemplary (4). Add the four scores to produce a total out of 16.

- 4 to 7: Beginning overall
- 8 to 10: Developing overall
- 11 to 13: Proficient overall
- 14 to 16: Exemplary overall

Report the total alongside the four individual criterion levels so students can see strengths and areas for revision.

## Notes for the teacher

- Distinguish between arithmetic slips and conceptual misunderstanding when scoring the calorimetry and Hess' law criteria; a single unit error should not drop a student a full level if the method is sound.
- When students select their own reaction examples (such as combustion or photosynthesis), confirm the classification against accepted thermochemical values before scoring [Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23643).
- Students should be able to analyze and label energy diagrams of a chemical reaction, including reactants, products, enthalpy change and activation energy[Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23653).
- Keep the illustrative examples in the source outcomes separate from required content; do not penalize students for choosing different reactions than those discussed in class.

---
*AILI marking guide · language en · model claude-sonnet-5 · generated 2026-09-17 · id b33b5ac7-15cc-4c36-997e-b983d3a1797c*

### Sources

- node:n1: Unit A: Thermochemical Changes (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23632)
- node:n2: General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23633)
- node:n3: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634)
- node:n4: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636)
- node:n5: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638)
- node:n6: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23639)
- node:n7: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23640)
- node:n8: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23641)
- node:n9: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23643)
- node:n10: General Outcome 2 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23650)
- node:n11: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23652)
- node:n12: Specific Outcomes for Knowledge (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23653)