Find the number of molecules,number of carbon atoms,number of hydrogen atoms,and total number of atoms in $5.6 \ L$ of $CH_4$ at $STP$.

(N/A) At $STP$,$22.4 \ L$ of any gas contains $6.022 \times 10^{23}$ molecules (Avogadro's number).
Number of moles of $CH_4 = \frac{5.6 \ L}{22.4 \ L/mol} = 0.25 \ mol$.
Number of molecules of $CH_4 = 0.25 \times 6.022 \times 10^{23} = 1.5055 \times 10^{23}$ molecules.
Number of $C$ atoms $= 1 \times 1.5055 \times 10^{23} = 1.5055 \times 10^{23}$ atoms.
Number of $H$ atoms $= 4 \times 1.5055 \times 10^{23} = 6.022 \times 10^{23}$ atoms.
Total number of atoms $= 1.5055 \times 10^{23} + 6.022 \times 10^{23} = 7.5275 \times 10^{23}$ atoms.