Final answer:
Percentage error in calorimetry can occur due to factors such as heat absorbed by the calorimeter itself, use of less insulated coffee cup calorimeters, calibration errors, and measuring inaccuracies, aside from heat loss to the environment.
Step-by-step explanation:
The question pertains to why there may still be a percentage error in calorimetry aside from heat loss. Besides heat loss, errors in calorimetry can occur due to several factors. When performing calorimetry, it is crucial to account for the heat absorbed not only by the solution but also by the calorimeter itself.
This becomes significant particularly when the heat absorbed by the calorimeter is too large to neglect for obtaining accurate results.
Scientists use well-insulated calorimeters to limit heat transfer and improve accuracy. However, in educational settings, such as general chemistry classes, students often use simpler coffee cup calorimeters made from polystyrene cups.
These are less insulated and therefore allow more heat exchange with the outside environment, leading to less accurate energy values. Calibration errors, measuring inaccuracies, and incomplete reactions can also contribute to the percentage error in calorimetry experiments.
It is essential to understand that according to the law of conservation of energy, during a chemical reaction, the sum of the heat produced or consumed by the reaction and the heat absorbed or lost by the solution and calorimeter should be zero.
Any deviation from this indicates an error. Ideally, in a calorimetry experiment, if a high-temperature substance (like metal) is placed in a low-temperature substance (like water), the two should reach thermal equilibrium without any heat gain or loss by the calorimeter or its surroundings, resulting in a net heat change of zero.