When 2.00 g of methane are burned in a bomb calorimeter, the change in temperature is 3.08°c. the heat capacity of the calorimeter is 2.68 kj/°c. the molar mass of methane is 16.042 g/mol. what is the approximate molar enthalpy of combustion of this substance?

The approximate molar enthalpy of combustion of this substance is -66 kJ/mole.

Explanation:

First we have to calculate the heat gained by the calorimeter.

where,

q = Heat gained = ?

c = Specific heat =

ΔT =  The change in temperature = 3.08°C

Now put all the given values in the above formula, we get:

Now we have to calculate molar enthalpy of combustion of this substance :

where,

= enthalpy change = ?

q = heat gained = 8.2544kJ

n = number of moles methane =

Therefore,  the approximate molar enthalpy of combustion of this substance is -66 kJ/mole.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.