Question

A sample of Ni(CO)4, a toxic transition-metal complex, has 5.23 x 10^24 atoms of carbon. How many atoms of Ni does it contain?

A. 6.02 x 10^23 atoms
B. 1.50 x 10^23 atoms
C. 1/4 atom
D. 20.9 x 10^23 atoms
E. 1.31 x 10^24 atoms

Answer 1

Answer: The correct answer is Option E.

Step-by-step explanation:

We are given a chemical compound having formula
`Ni(CO)_4`

In 1 mole of the compound, 1 mole of nickel atom, 4 moles of carbon atom and 4 moles of oxygen atom are present.

According to mole concept:

1 mole of a substance contains
`6.022\time 10^(23)` number of particles

Number of carbon atoms in compound =
`4* 6.022* 10^(23)`

Number of nickel atoms in compound =
`1* 6.022* 10^(23)`

We are given:

Number of carbon atoms =
`5.23* 10^(24)`

To calculate the number of nickel atoms for given amount of carbon atom, we use unitary method:

When
`4* 6.022* 10^(23)` number of carbon atoms are present, then
`6.022* 10^(23)` number of nickel atoms are also present.

So, when
`5.23* 10^(24)` number of carbon atoms are present, then
`(4* 6.022* 10^(23))/(6.022* 10^(23))* 5.23* 10^(24)=1.31* 10^(24)` number of nickel atoms are also present.

Hence, the correct answer is Option E.

Answer 2

In Ni(CO)₄ the stoichiometry of Ni to C is 1:4
for every 4 atoms of C is attached to one Ni atom.
this means that if there are 4 atoms of C - 1 atom of Ni
in 5.23 x 10²⁴ atoms of C -1/4 x 5.23 x 10²⁴ atoms of Ni
= 1.3075 x 10²⁴ atoms of Ni
the number of atoms rounded off to the second decimal place = 1.31 x 10²⁴ atoms
correct answer is E