# Journal Prompt: The Limits of Your Calorimeter

Every calorimetry experiment contains built-in error. Understanding where error comes from separates a skilled chemist from someone who simply inserts numbers into a formula.

**Suppose you completed a calorimetry experiment to find the molar enthalpy of a combustion reaction. Your calculated ΔH had a smaller magnitude than the accepted value. Write a journal entry. Explain at least two specific sources of heat loss or measurement error that could cause this difference. Describe how each source would affect your calculated Q = mcΔt value ([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)).**

### Where to start:

- What assumption does Q = mcΔt make about where the heat released actually goes?
- Where might thermal energy escape before your thermometer or probe registers it?
- Does your calorimeter design (a polystyrene cup versus an open container) change how much heat is lost to the surroundings?
- How would incomplete combustion affect the amount of energy actually released, apart from measurement error?

### Stretch:

Use ΔH notation to calculate the energy change in a chemical reaction. Explain using ΔH notation how you would expect the reported molar enthalpy to move closer to the accepted value if your change succeeded ([Outcome](https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638)).

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*AILI prompt · language en · model claude-sonnet-5 · generated 2026-09-17 · id 8f38c8db-23e0-46aa-973d-d65f2c5e10e3*

### Sources

- node:n1: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636)
- node:n2: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634)
- node:n3: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23641)
- node:n4: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23647)
- node:n5: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23634)
- node:n6: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23636)
- resource:r1: Resources › type#activity › SCN3796 (https://goa-cc-uat-aili-app-001.azurewebsites.net/library/resource/9ykNTynh306g6EnZlkTITQ)
- node:n7: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23638)
- node:n8: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23633)
- node:n9: Chemistry › Chemistry (20, 30) › Chemistry 30 › Unit A: Thermochemical Changes › General Outcome 1 (https://goa-cc-uat-aili-app-001.azurewebsites.net/explore/node/23648)
- resource:r2: Resources › type#activity › SCN3796 (https://goa-cc-uat-aili-app-001.azurewebsites.net/library/resource/0uxhxD914kqzmssVwCK4tg)