Understanding Bomb Calorimeters: Measuring ΔE and ΔH for Calorimetry Homework

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SUMMARY

Bomb calorimeters are specifically designed to measure the change in internal energy (ΔE) of a system, while coffee cup calorimeters measure the change in enthalpy (ΔH). The relationship between these two is defined by the equation ΔH = ΔE + PΔV, where P is pressure and ΔV is the change in volume. In bomb calorimeters, the volume remains constant, leading to the conclusion that ΔH equals ΔE under these conditions. Therefore, the work done is negligible, and the energy change is primarily due to thermal energy transfer.

PREREQUISITES
  • Understanding of thermodynamic concepts such as internal energy and enthalpy.
  • Familiarity with calorimetry principles and the function of bomb calorimeters.
  • Knowledge of the ideal gas law and its implications in thermodynamic processes.
  • Basic algebra to manipulate thermodynamic equations.
NEXT STEPS
  • Study the differences between bomb calorimeters and coffee cup calorimeters in detail.
  • Learn about the implications of constant volume processes in thermodynamics.
  • Explore the derivation and applications of the equation ΔH = ΔE + PΔV.
  • Investigate the role of pressure and volume changes in calorimetry experiments.
USEFUL FOR

Chemistry students, educators, and professionals involved in thermodynamics and calorimetry, particularly those focused on energy measurements in chemical reactions.

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Homework Statement


My book says that bomb calorimeters are used to measure ΔE while coffee cup calorimeters are used to measure ΔH. Isn't ΔE for bomb calirometers the same as ΔH?

Homework Equations

The Attempt at a Solution


Bomb Calorimeter:
ΔH = ΔE + PΔV = ΔE (since, constant volume).
So ΔH = ΔE.
So does that mean no work is done in bomb calorimeters and the change in energy is entirely due to the transfer of thermal energy?
 
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You have written wrong equation.
It is actually ΔH= ΔE + ΔPV
 
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