Question

Calculate the number of gold atom

present in 0.6g of 18 carat gold (24 carat
gold is taken as 100%
where and amu of
gold in 197
Teacher's Signature.

Answer 1

The number of gold atom : 1.204 x 10²¹

Further explanation

Given

0.6 g of 18 carat gold

mass number of gold = 197

24 carat as 100% gold

Required

The number of gold atom

Solution

Percentage of gold in 18 carat :

`\tt (18)/(24)* 100\%=75\%`

Mass of gold in 0.6 g of 18 carat :

`\tt 75\%* 0.6~g=0.45~g`

mol :

`\tt mol=(mass)/(MW)=(0.45)/(197)=0.0023`

A mole is a number of particles(atoms, molecules, ions) in a substance

1 mole = 6.02.10²³ particles

So the number of gold atom :

`\tt 0.0023* 6.02* 10^(23)=1.204* 10^(21)`