How to Find out the Enthalpy Change in a Bomb Calorimeter

The first law of thermodynamics states that, when energy passes into or out of a system (as work, heat, or matter), the system's internal energy changes in accordance with the law of conservation of energy.


No work is done as the chemical reaction is carried out at constant volume in a bomb calorimeter.

Question:

1 g of graphite is burnt in a bomb calorimeter in excess of oxygen at 298 K & 1 atm according to the following equation:

C(s) (graphite) + O2(g) → CO2(g)

During the reaction, temperature rises from 298 K to 299 K. If the heat capacity of the bomb calorimeter is 20.7 kJ/K, what is the enthalpy change for the above reaction at 298 K & 1 atm?

Solution:



Click to enlarge the image

q = Heat, Cv = Heat capacity at constant volume, Î”T = Change in absolute temperature, w = Work done, Î”U = Change in internal energy, Î”H = Change in enthalpy, Î”ng = Change in moles of gaseous molecules, R = Universal gas constant, T = Absolute temperature, wchoric = Work done at constant volume

Intrigued by thermodynamics❓ Let Chemaficionado know at mychemistryhomework@gmail.com❗

References:
(1)    Wikipedia Contributors. Laws of thermodynamics. Wikipedia. https://en.wikipedia.org/wiki/Laws_of_thermodynamics.

(2)    Ncert. Chemistry : Textbook for Class XI - Part.I; National Council Of Educational Research And Training: New Delhi.

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