Q. 755.0( 4 Votes )

# Assume that each atom in a copper wire contributes one free electron. Estimate the number of free electrons in a copper wire having a mass of 6.4 g (take the atomic weight of copper to be 64 g mol^{–1}).

Answer :

**Given:**Atomic weight of copper = 64 g mol

^{-1}

Mass of copper wire : m = 6.4 g

**Formula used:**

We know that,

Number of moles in 64 g of copper = 1

Thus, number of moles in 6.4 g of copper = 0.1

Also,

Number of atoms in one mole=N

_{A}

Here, N

_{A}is the Avogadro Number : N

_{A}= 6.023× 10

^{23}atoms

∴No.of atoms in 0.1 mole of copper=0.1× 6.023× 10

^{23}

∴No.of atoms in 0.1 mole of copper=0.1× 6.023× 10

^{22}

It is given that each atom contributes one free electron,

Therefore in 0.1 mole of copper will contribute

Hence, there will be free electron in 6.4 g of copper.

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