Find moles of electrons present in 64 g of CH_4

Options

A. 64
B. 40
C. 24
D. 16

Answer

To find the moles of electrons present in 64 g of CH₄ (methane), we can follow these steps:

### Step 1: Calculate the molar mass of CH₄
- The molar mass of carbon (C) is approximately 12 g/mol.
- The molar mass of hydrogen (H) is approximately 1 g/mol.
- CH₄ consists of 1 carbon atom and 4 hydrogen atoms.

\[ \text{Molar mass of CH}_4 = (1 \times 12) + (4 \times 1) = 12 + 4 = 16 \text{ g/mol} \]

### Step 2: Calculate the number of moles of CH₄ in 64 g
- Use the formula for moles:

\[ \text{Moles of CH}_4 = \frac{\text{Given mass}}{\text{Molar mass}} = \frac{64 \text{ g}}{16 \text{ g/mol}} = 4 \text{ moles} \]

### Step 3: Calculate the total number of electrons in CH₄
- In CH₄, the carbon atom contributes 6 electrons (since it has 4 valence electrons) and each hydrogen atom contributes 1 electron.
- Therefore, the total number of electrons in one molecule of CH₄ is:

\[ \text{Total electrons in CH}_4 = 6 \text{ (from C)} + 4 \text{ (from 4 H)} = 10 \text{ electrons} \]

### Step 4: Calculate the total number of moles of electrons in 4 moles of CH₄
- Since there are 10 electrons in one mole of CH₄, for 4 moles of CH₄, the total number of moles of electrons will be:

\[ \text{Total moles of electrons} = 4 \text{ moles of CH}_4 \times 10 \text{ electrons/mole} = 40 \text{ moles of electrons} \]

### Final Answer:
The total moles of electrons present in 64 g of CH₄ is **40 moles**.

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