Question

In three moles of ethane $(\text{C}_2\text{H}_6)$, calculate the following:
(i) Number of moles of carbon atoms.
(ii) Number of moles of hydrogen atoms.
(iii) Number of molecules of ethane.

Answer 1

(i) 1 mole of $(\text{C}_2\text{H}_6)$ contains 2 moles of carbon atoms.
Number of moles of carbon atoms in 3 moles of $(\text{C}_2\text{H}_6)$
= 2 × 3 = 6

---

(ii) 1 mole of $(\text{C}_2\text{H}_6)$ contains 6 moles of hydrogen atoms.
Number of moles of carbon atoms in 3 moles of $(\text{C}_2\text{H}_6)$
= 3 × 6 = 18

---

(iii) 1 mole of $(\text{C}_2\text{H}_6)$ contains 6.023 × 10 23 molecules of ethane.
Number of molecules in 3 moles of $(\text{C}_2\text{H}_6)$
$= 3 × 6.023 × 10^{ 23} = 18.069 × 10^{23}$