Answer:
3.61 * 10 ²⁴atoms.
Explanation:
Moles is denoted by given mass divided by the molecular mass ,
Hence ,
n = w / m
n = moles ,
w = given mass ,
m = molecular mass .
From the question ,
w = 582 g
m = 194 g/mol
The number of moles can be calculated from the above formula , and substituting the respective values ,
n = w / m = 582 g / 194 g/mol = 3 mol
In the molecular formula of caffeine ,
<u>In 1 mole of caffeine their are - 2 moles of Oxygen.
</u>
Therefore , in 3 moles of Caffeine there will be 6 moles of oxygen.
As well know ,
one mole of any substance contains 6.023*10²³ atoms,
Therefore , in 6 mol of oxygen = 6 * 6.023*10²³ atoms = 3.61 * 10 ²⁴atoms.
[Co(NH₃)₅Br]²⁺
Ligands and charges on them,
5 × NH₃ = 5 × 0 = 0
1 × Br⁻¹ = 1 × -1 = -1
Charge on sphere = +2
So, putting values in equation,
Co + (0)₅ - 1 = +2
Co + 0 - 1 = +2
Co - 1 = +2
Co = +2 + 1
Co = +3
Result:
Oxidation state of Co in [Co(NH₃)₅Br]²⁺ is +3.
