Chapter 13, Problem 2P

To determine

The number of atoms in a 3.4 g copper coin

Answer to Problem 2P

Solution:

The number of atoms in the copper coin is $3.22\times {10}^{22}$

Explanation of Solution

Given:

Mass of copper coin, m_c = 3.4 g

Formula used:

                   i)The number of moles of a given specimen of substance,

                  n = $\frac{m}{M}$, where m is the mass of the specimen and M is the mass of 1 mole of the substance

Calculation:

The number of moles of atoms of a specimen of a monatomic substance is given by,

n = $\frac{m}{M}$, where m is the mass of the specimen and M is the mass of 1 mole of the substance

For copper, $M_c=63.55g/mol$

Therefore, n = $\frac{3.4g}{63.55g/mol}$

$=0.053mol$

Number of atoms of copper, $N=n\times N_A$, where N_A is the Avogadro number

or $N=0.053\times 6.023\times {10}^{23}$

$=3.22\times {10}^{22}$