Question

How many atoms are there in 18 grams of silver

Answer 1

Answer:

Number of atoms= $1.004\times 10^{23}$ atoms

Explanation:

1 mole is the mass of substance which contain $6.022\times 10^{23}$

particles of that substance.Its symbol is 'n'.

Here the quantity$6.022\times 10^{23}$ is called Avogadro number and it is denoted by $N_{0}$.

Mass of the substance in grams is called is molar mass.It is denoted by'M'

Moles can be calculated by :

1) $n=\frac{given\ mass}{molar\ mass}=\frac{w}{M}$

2)$n=\frac{Number\ of\ particles}{Avogadro\ number}=\frac{N}{N_{0}}

$

compare 1) and 2) formula, we get

$\frac{N}{N_{0}=\frac{w}{M}[tex].................(i)

For silver (Ag), M=107.86 g

w=18 g  (given) and [tex]{N_{0}=6.022\times 10^{23}$

Put the values of w,M and ${N_{0}[tex] in equation (i) and solve for N

[tex]\frac{N}{6.022\times 10^{23}}=\frac{18}{107.86}$

$N=\frac{18}{107.86}\times 6.022\times 10^{23}$

$N= 1.004\times 10^{23}[tex]

Hence Number of atoms of silver= [tex]1.004\times 10^{23}$ atoms