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$(A)$ Atoms of different elements differ in mass.
$(B)$ Matter consists of divisible atoms.
$(C)$ Compounds are formed when atoms of different element combine in a fixed ratio.
$(D)$ All the atoms of given element have different properties including mass.
$(E)$ Chemical reactions involve reorganisation of atoms.
Choose the correct answer from the options given below :
$C ( s )+\frac{1}{2} O _{2}( g ) \rightarrow CO ( g )+100 \;kJ$
When coal of purity $60 \%$ is allowed to burn in presence of insufficient oxygen, $60 \%$ of carbon is converted into $'CO'$ and the remaining is converted into $'CO _{2}$$'$.
The heat generated when $0.6 \;kg$ of coal is burnt is
