Question.
In three moles of ethane $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)$, calculate the following:
(i)Number of moles of carbon atoms.
(ii)Number of moles of hydrogen atoms.
(iii)Number of molecules of ethane
In three moles of ethane $\left(\mathrm{C}_{2} \mathrm{H}_{6}\right)$, calculate the following:
(i)Number of moles of carbon atoms.
(ii)Number of moles of hydrogen atoms.
(iii)Number of molecules of ethane
Solution:
(i) 1 mole of $\mathrm{C}_{2} \mathrm{H}_{6}$ contains 2 moles of carbon atoms.
$\therefore$ Number of moles of carbon atoms in 3 moles of $\mathrm{C}_{2} \mathrm{H}_{6}$
= 2 × 3 = 6
(ii) 1 mole of $\mathrm{C}_{2} \mathrm{H}_{6}$ contains 6 moles of hydrogen atoms.
$\therefore$ Number of moles of carbon atoms in 3 moles of $\mathrm{C}_{2} \mathrm{H}_{6}$
$=3 \times 6=18$
(iii) 1 mole of $\mathrm{C}_{2} \mathrm{H}_{6}$ contains $6.023 \times 10^{23}$ molecules of ethane.
$\therefore$ Number of molecules in 3 moles of $\mathrm{C}_{2} \mathrm{H}_{6}$
$=3 \times 6.023 \times 10^{23}=18.069 \times 10^{23}$
(i) 1 mole of $\mathrm{C}_{2} \mathrm{H}_{6}$ contains 2 moles of carbon atoms.
$\therefore$ Number of moles of carbon atoms in 3 moles of $\mathrm{C}_{2} \mathrm{H}_{6}$
= 2 × 3 = 6
(ii) 1 mole of $\mathrm{C}_{2} \mathrm{H}_{6}$ contains 6 moles of hydrogen atoms.
$\therefore$ Number of moles of carbon atoms in 3 moles of $\mathrm{C}_{2} \mathrm{H}_{6}$
$=3 \times 6=18$
(iii) 1 mole of $\mathrm{C}_{2} \mathrm{H}_{6}$ contains $6.023 \times 10^{23}$ molecules of ethane.
$\therefore$ Number of molecules in 3 moles of $\mathrm{C}_{2} \mathrm{H}_{6}$
$=3 \times 6.023 \times 10^{23}=18.069 \times 10^{23}$