The mass of `1` mol of electrons is

Options

A. a.`9.1 xx 10^(-28) g`
B. b.1.008 mg
C. c.0.55 mg
D. d.`9.1 xx 10^(-27) g`

Explanation

To find the mass of 1 mole of electrons, we can follow these steps:

### Step 1: Determine the mass of a single electron.
The mass of one electron is given as:
\[ m_e = 9.1 \times 10^{-31} \text{ kg} \]

### Step 2: Convert the mass of an electron to grams.
Since 1 kg = 1000 grams, we convert the mass of an electron to grams:
\[ m_e = 9.1 \times 10^{-31} \text{ kg} \times \frac{1000 \text{ g}}{1 \text{ kg}} = 9.1 \times 10^{-28} \text{ g} \]

### Step 3: Use Avogadro's number to find the mass of 1 mole of electrons.
Avogadro's number (\(N_A\)) is approximately:
\[ N_A = 6.022 \times 10^{23} \text{ electrons/mol} \]

The mass of 1 mole of electrons can be calculated by multiplying the mass of a single electron by Avogadro's number:
\[ \text{Mass of 1 mole of electrons} = N_A \times m_e \]
\[ = 6.022 \times 10^{23} \text{ electrons/mol} \times 9.1 \times 10^{-28} \text{ g/electron} \]

### Step 4: Perform the multiplication.
Calculating the above expression:
\[ \text{Mass of 1 mole of electrons} = 6.022 \times 9.1 \times 10^{-5} \text{ g} \]
\[ = 54.8 \times 10^{-5} \text{ g} \]

### Step 5: Convert the mass from grams to milligrams.
Since 1 gram = 1000 milligrams, we convert the mass to milligrams:
\[ \text{Mass in mg} = 54.8 \times 10^{-5} \text{ g} \times \frac{1000 \text{ mg}}{1 \text{ g}} \]
\[ = 54.8 \times 10^{-2} \text{ mg} \]
\[ = 0.548 \text{ mg} \]

### Step 6: Round the final answer.
Rounding 0.548 mg gives us approximately:
\[ \text{Mass of 1 mole of electrons} \approx 0.55 \text{ mg} \]

### Final Answer:
The mass of 1 mole of electrons is approximately **0.55 milligrams**.

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