In a constant volume calorimeter, `3.5 g` of a gas with molecular weight `28` was burnt in excess oxygen at `298.0 K`. The temperature of the calorimeter was found to increase from `298.0 K to 298.45 K` due to the combustion process. Given that the heat capacity of the calorimeter is `2.5 kJ K^(-1)`, find the numerical value for the enthalpy of combustion of the gas in `kJ mol^(-1)`

Explanation

To find the enthalpy of combustion of the gas in kJ/mol, we can follow these steps:

### Step 1: Calculate the number of moles of the gas
Given:
- Mass of the gas = 3.5 g
- Molecular weight of the gas = 28 g/mol

The number of moles (n) can be calculated using the formula:
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