Question

Find out the total number of electrons present in 3.2 g methane?

• A. $6.022\times10^{23}$
• B. $1.204\times10^{24}$
• C. $3.201\times10^{23}$
• D. $4.821\times10^{22}$

Hint:

Mole concept workflow for particle counting:
Mass $\xrightarrow{\div \text{ Molar Mass}}$ Moles $\xrightarrow{\times N_A}$ Molecules $\xrightarrow{\times \text{ Particles/molecule}}$ Total Particles.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
To find the total electrons, we first determine the number of moles of the substance, then the number of molecules, and finally multiply by the electrons per molecule.

Step 2: Formula Application:
1. Moles of $CH_4 = \frac{\text{Given Mass}}{\text{Molar Mass}}$ 2. Electrons in 1 molecule of $CH_4$ = Electrons in $C$ (6) + 4 $\times$ Electrons in $H$ (1) = 10 electrons.

Step 3: Explanation:
Moles of $CH_4 = \frac{3.2}{16} = 0.2$ mol. Number of molecules = $0.2 \times 6.022 \times 10^{23} = 1.2044 \times 10^{23}$ molecules. Total electrons = $10 \times 1.2044 \times 10^{23} = 1.2044 \times 10^{24}$ electrons.

Step 4: Final Answer:
The total number of electrons is 1.204 $\times$ 10$^{24}$.