Question

5
45.) From 200 mg of Co, when x molecules are removed.
2.89'10-moles of CO2 are left
. x will be
(1) 1020 molecules (2) 1010 molecules
(3) 21 molecules (4) 1021 molecules​

Answer 1

From 200 mg of Co, when x molecules are removed.

2.89'10-moles of CO2 are left

. x will be option D 1021 molecules

Molar Mass of CO2​=44 g 

Mass given =200 mg=0.2 g 

No. of moles =440.2​=2201​=4.54×10−3 

Change in no. of moles = (4.54−2.89)×10−3 = 1.65×10−3

No. of molecules associated with these much moles = 6.022×1023×1.65×10−3≈1021