Question

How many atoms of cobalt would there be in a 2.2 gram sample of cobalt

Answer 1

Atomic mass Co = 58.93 u.m.a

58.93 g ------------------------ 6.02x10²³ atoms
2.2 g ---------------------------- ( atoms ?)

2.2 x (6.02x10²³) / 58.93

= 1.3244x10²⁴ / 58.93

= 2.24x10²² atoms

hope this helps!

Answer 2

Answer : The number of atoms of cobalt are,
`2.246* 10^(22)`

Explanation : Given,

Mass of cobalt sample = 2.2 g

Molar mass of Cobalt = 58.93 g/mole

First we have to calculate the moles of cobalt.

`\text{Moles of }Co=\frac{\text{Mass of }Co}{\text{Molar mass of }Co}=(2.2g)/(58.93g/mole)=0.0373moles`

Now we have to calculate the number of atoms present in cobalt sample.

As, 1 mole of cobalt sample contains
`6.022* 10^(23)` number of cobalt atoms

So, 0.0373 mole of cobalt sample contains
`0.0373* 6.022* 10^(23)=2.246* 10^(22)` number of cobalt atoms

Therefore, the number of atoms of cobalt are,
`2.246* 10^(22)`