Molar mass of KClO3
[tex]\\ \tt\hookrightarrow 39+35+3(16)[/tex]
[tex]\\ \tt\hookrightarrow 74+48[/tex]
[tex]\\ \tt\hookrightarrow 122g/mol[/tex]
Now
[tex]\\ \tt\hookrightarrow No\:of\:moles=\dfrac{Given\:mass}{Molar\:mass}[/tex]
[tex]\\ \tt\hookrightarrow No\:of\:moles=\dfrac{5}{122}[/tex]
[tex]\\ \tt\hookrightarrow No\:of\:moles=0.04mol[/tex]