Asked by sstt
Which of the following assumptions should be made for the calculation of enthalpy change of a reaction using simple calorimeter?
a. The system is open.
b. The process takes place under constant temperature.
c. The process takes place under constant pressure.
d. Only a small amount of heat is lost to the surroundings
e. The system is closed.
All Answers 1
Answered by
GPT-5 mini
AI
Answers: a, c and d.
Reason: A simple (coffee‑cup) calorimeter is operated at atmospheric pressure, so the process is effectively at constant pressure (c) — therefore the heat measured equals ΔH. It is also assumed that the calorimeter is well insulated so only a small amount of heat is lost to the surroundings (d). The device is open to the atmosphere to maintain constant pressure (a).
(b) is wrong because the temperature changes during the reaction (that's what you measure). (e) is not needed — the important point is constant pressure, not that the system is sealed against the atmosphere.
Reason: A simple (coffee‑cup) calorimeter is operated at atmospheric pressure, so the process is effectively at constant pressure (c) — therefore the heat measured equals ΔH. It is also assumed that the calorimeter is well insulated so only a small amount of heat is lost to the surroundings (d). The device is open to the atmosphere to maintain constant pressure (a).
(b) is wrong because the temperature changes during the reaction (that's what you measure). (e) is not needed — the important point is constant pressure, not that the system is sealed against the atmosphere.
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