When $0.400\ \mathrm g$ $\ce{CH4}$ is burned in excess oxygen in a bomb calorimeter that has a heat capacity of $3245\ \mathrm{J/^\circ C}$ a temperature increase of $6.795\ \mathrm{^\circ C}$ is observed. What is the value of $Q_V$?

I thought it was the regular $Q=mc\Delta T$ problem but it isn't and not only that I did the equation but it didn't work.

I am not sure what to do right here at the moment

Using the data determine standard enthalpy change for the combustion of methane

Also I would like the definition of the standard enthalpy change and what it tells you and the purpose of it.


Heat of combustion is the amount of heat (enthalpy) liberated when 1 mole $\ce{CH4}$ reacts (combusts) with oxygen.

In other words, what is the heat of reaction in this case?

$\ce{CH4(g) + 2O2(g) -> CO2(g) + 2H2O(l)}$

Then you must ask yourself, what happens after the heat is produced i.e. where does it go? It quickly turns into an accounting problem...

Take a look at: Constant Volume Calorimetry

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