Question

In a particular mass of kau(cn)2, there are 6.66 × 1020 atoms of gold. What is the total number of atoms in this sample?

Answer 1

Total number of atoms in the sample is the sum of number of atoms of all the elements present in the sample.

Number of gold,
`Au` atoms in
`KAu(CN)_2` =
`6.66* 10^(20)` atoms (given)

From the formula of compound that is
`KAu(CN)_2` it is clear that the number of potassium and gold are same whereas those of carbon and nitrogen are 2 times of them.

So, the number of atoms of each element is:

Number of potassium,
`K` atoms in
`KAu(CN)_2` =
`6.66* 10^(20)` atoms

Number of carbon,
`C` atoms in
`KAu(CN)_2` =
`2*6.66* 10^(20)` atoms =
`13.32* 10^(20)`

Number of nitrogen,
`N` atoms in
`KAu(CN)_2` =
`2*6.66* 10^(20)` atoms =
`13.32* 10^(20)`

Total number of atoms in
`KAu(CN)_2` = Number of gold,
`Au` atoms+Number of potassium,
`K` atoms +Number of carbon,
`C` atoms + Number of nitrogen,
`N` atoms

Total number of atoms in
`KAu(CN)_2` =
`6.66* 10^(20)+6.66* 10^(20)+13.32* 10^(20)+13.32* 10^(20)`

Total number of atoms in
`KAu(CN)_2` =
`39.96* 10^(20)` atoms

Hence, the total number of atoms in
`KAu(CN)_2` is
`3.996* 10^(21)` atoms.