(a) 1 mole contains two moles of C- atoms.
∴ No. of moles of C- atoms in 3 moles of
= 2 * 3
= 6
(b) 1 mole contains six moles of H- atoms.
∴ No. of moles of C- atoms in 3 moles of
= 3 * 6
= 18
(c) 1 mole contains 1 mole of ethane- atoms.
∴ No. of molecules in 3 moles of
=
=