Estimate the number of free electrons in a copper wire possessing a mass of 64 g , assuming that each atom contributes one free electron (take the atomic weight of copper as 64 g mol^ -1 ).

Correct answer: B. 6.02 × 10^ 23 Number of moles of copper is given by n = Mass Atomic weight = (64)/(64) = 1 mol Number of copper atoms in 1 mol is equal to Avogadro's number, N_A = 6.02 × 10^ 23 Since each copper atom contributes one free electron, the total number of free electrons is equal to the number of copper atoms. Number of free electrons = 6.02 × 10^ 23

Concepts Of Physics MCQ Edition [Volume 2]

Exam: Concepts Of Physics MCQ Edition [Volume 2]
Subject: Physics
Chapter: Electric Field and Potential

Concepts Of Physics MCQ Edition [Volume 2] · Physics · Electric Field and Potential

Estimate the number of free electrons in a copper wire possessing a...

Estimate the number of free electrons in a copper wire possessing a mass of

64 \text{ g}

, assuming that each atom contributes one free electron (take the atomic weight of copper as

64 \text{ g mol}^{-1}

Options

A $6.02 \times 10^{22}$
B $6.02 \times 10^{23}$
C $3.01 \times 10^{23}$
D $1.20 \times 10^{24}$

Correct answer

B. $6.02 \times 10^{23}$

Step-by-step solution

Number of moles of copper is given by

n = \dfrac{\text{Mass}}{\text{Atomic weight}} = \dfrac{64}{64} = 1 \text{ mol}

Number of copper atoms in

1 \text{ mol}

is equal to Avogadro's number,

N_A = 6.02 \times 10^{23}

Since each copper atom contributes one free electron, the total number of free electrons is equal to the number of copper atoms.

Number of free electrons

= 6.02 \times 10^{23}

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