Respuesta :
Answer:
There are approximately 1.54 moles in a 275 g sample of [tex]K_2CrO_3[/tex].
Explanation:
To find out number of moles, fistly we have to calculate molecular mass of [tex]K_2CrO_3[/tex].
There are 2 atoms of Potassium 1 atom of Chromium and 3 atoms of oxygen in the given compound.
For molecular mass we have to add the value of mass of 2 atoms of Potassium with mass of 1 atom of Chromium and with mass of 3 atoms of oxygen.
Atomic mass of Potassium = 39
Atomic mass of Chromium = 52
Atomic mass of Oxygen = 16
Now,
Molecular mass of [tex]K_2CrO_3[/tex] = [tex]2\times 39+52+3\times 16=78+52+48=178\ gm[/tex]
The molecular mass of a compound is the mass of compound in one mole.
To find out the number of moles, we have to divide given mass of compound by its molecular mass.
[tex]Number\ of\ moles=\frac{given\ mass}{molecular\ mass}[/tex]
[tex]Number\ of\ moles=\frac{275}{178}= 1.54[/tex]
Hence the number of moles in 275 gm of [tex]K_2CrO_3[/tex] is 1.54.
