The mass of 5 mole of electron is:

Options

A. 6.24×`10^(−7)Kg`
B. 2.73×`10^(−6)Kg`
C. 1.64×`10^(−6)Kg`
D. None of these

Explanation

To find the mass of 5 moles of electrons, we can follow these steps:

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

### Step 2: Determine the number of electrons in one mole
We know that one mole of any substance contains Avogadro's number of particles, which is:
\[ N_A = 6.02 \times 10^{23} \]
Thus, one mole of electrons contains \( 6.02 \times 10^{23} \) electrons.

### Step 3: Calculate the number of electrons in 5 moles
To find the total number of electrons in 5 moles, we multiply the number of electrons in one mole by 5:
\[ \text{Total electrons in 5 moles} = 5 \times N_A = 5 \times 6.02 \times 10^{23} \]

### Step 4: Calculate the total mass of 5 moles of electrons
The total mass of 5 moles of electrons can be calculated using the formula:
\[ \text{Total mass} = \text{mass of one electron} \times \text{total number of electrons} \]
Substituting the values we have:
\[ \text{Total mass} = m_e \times (5 \times N_A) \]
\[ \text{Total mass} = 9.1 \times 10^{-31} \text{ kg} \times (5 \times 6.02 \times 10^{23}) \]

### Step 5: Perform the calculation
Now we can perform the calculation:
1. Calculate \( 5 \times 6.02 \times 10^{23} = 3.01 \times 10^{24} \)
2. Now, multiply this by \( 9.1 \times 10^{-31} \):
\[ \text{Total mass} = 9.1 \times 10^{-31} \text{ kg} \times 3.01 \times 10^{24} \]
\[ \text{Total mass} = 2.7431 \times 10^{-6} \text{ kg} \]
Rounding this gives:
\[ \text{Total mass} \approx 2.73 \times 10^{-6} \text{ kg} \]

### Final Answer
The mass of 5 moles of electrons is:
\[ \text{Mass} = 2.73 \times 10^{-6} \text{ kg} \]

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