Calorific Value

Calorific value is defined as heat produced by complete combustion of a specific quantity of a fuel . It is usually expressed in joules per kilogram. An ideal fuel is one which is having high calorific value.

Barometer: To measure pressure.

Bomb calorimeter: To measure the heat output of combustion.

Spectrometer: To measure the absorption of light.

Combustion chamber: Chamber used for combustion.

Calorific value is defined as the amount of energy released during combustion per unit mass of the substance.

Heat of combustion of ethane $=-\frac{745.6}{2}=-372.8;Kcal;mol^{-1}=-1559.79;KJ;mol^{-1}$       ($1;cal.=4.2;J$)

$2C _2H _6+7O _2\rightarrow 4CO _2+6H _2O$; $\Delta H=-745.6KCal$

The calorific value of a substance is the heat which it releases during combustion of its $1\text{ } gm$ solid.

The gross or high heating value is the amount of heat produced by the complete combustion of a unit quantity of fuel. 

The energy contained in a fuel or food, determined by measuring the heat produced by the complete combustion of a specified quantity of it. This is now usually expressed in joules per kilogram. Oxygen present in dry gaseous fuel does not contribute to its calorific value.

Calorimeter is the instrument used to measure calorific value of heat produced by combustible substances. Junker's calorimeter is used to determine the calorific value of gaseous fuels.

Calorific value of these gases are listed in table
Gober gas $= $  $5kWh/Nm^3$
refinery gas $= $ $1.5kWh/Nm^3$
Converte gas$ = $ $3kWh/Nm^3$
Blast furnace gas $=$  $0.9kWh/Nm^3$

Gross & net calorific value is the same for L.D converter gas. Calorific value is the total quantity of heat liberated by the complete combustion of a unit mass of the fuel in air or oxygen. It is expressed in $kcal/m^3$ or British thermal unit (B.T.U) per cubic foot.

Calorific value: The amount of energy produced by the complete combustion of a material or fuel.
Coal gas $H _2+CO+CH _4$ has the highest calorific value.

The calorific value of a fuel is the quantity of heat produced by its combustion, at constant pressure and under STP conditions. It is mainly expressed in kcal/g.

Petrol has highest calorifc value among all.
Petrol-48,000kJ/kg
Coke-31,000kJ/kg
Natural gas-43,000kJ/kg
Kerosene-46,200kJ/kg

Petrol is the combustible fuel with high calorific value which is used for the running automobiles like car, motorcycles etc.

Higher the heating value or higher the calorific value better the fuel is, so kerosene has a higher heating value which is measured by bomb calorimeter.

 Calorific value is the quantity of heat produced by the complete combustion of a given mass of a fuel, usually expressed in joules per kilogram. It can be defined as the amount of heat energy produced on complete combustion of 1 Kg of fuel.

Energy released by 12 kg of LPG =  12 %$\times$ 50 kJ $= $ 600 kJ
$\therefore$ energy consumed per day
$\displaystyle \frac {600,kJ}{30}, =, 20,000$ Joules/day.

Natural gas         $ = 43000 kJ/kg$

The calorific value is defined as the amount of heat released during complete combustion of a substance with oxygen under standard condition.

Calorific value is a measure of heating capacity of fuel. It gives the fuel efficiency.

The calorific value of a fuel is the quantity of heat produced by its combustion - at constant pressure and under a conditions known as " normal " of temperature and pressure (i.e. to 0oC and under a pressure of 1,013 mbar). 
The combustion of a fuel product generates water vapor. Certain techniques are used to recover the quantity of heat contained in this water vapor by condensing it. 
The Higher Calorific Value (or Gross Calorific Value - GCV) supposes that the water of combustion is entirely condensed and that the heat contained in the water vapor is recovered. 
The Lower Calorific Value (or Net Calorific Value - NCV) supposes that the products of combustion contains the water vapor. The heat contained in the water vapor is not recovered. 
LPG has a typical specific calorific value of 46.1 MJ/kg.
Calorific value of Bio gas is about 19 to 25 MJ/cubic meter, depending on the methane percentage in the biogas mix.
Heat of combustion of kerosene for lower heating value is 43.1 MJ/kg, and for higher heating value is 46.2 MJ/kg.
Petrol, calorific value of which is 45.8 MJ/kg.
Thus, LPG has highest calorific value among above.

Calorific value is the amount of energy produced by the complete combustion of a molecule. Amongst the given options, $H _{2}$ has the highest calorific value.