Question

how many moles in 25 g of caco3​

Answer 1

No of moles = mass/ molecular mass

Molecular mass of CaCO3 :

Ca = 40 u

C = 12 u

O3 = 3 x 16 = 48 u

Molecular mass = 40 + 12 + 48 = 100u.

Moles = 25 /100

Moles = 0.25

Hence their are 0.25 moles in 25g of caco3.

Answer 2

n/N=m/M

n=no. of moles

N=Avogadro's number=6.02×10^²³  

m=given mass=25g

M=molar mass=100(CaCO3)

⇒n/6.022 x 10^23=25/100

⇒n/6.022 x 10^23=1/4

⇒n=1/4 x 6.022 x 10^23

⇒n=6.022 x 10^23/4=1.5055 x 10^23 or 15055 x 10^19

hope it helps...........