Q. A sample of copper sulphate pentahydrate contains 8.64 g of oxygen. How many gram of Cu is present in this sample? (Atomic mass of Cu = 63.6, S = 32.06, O = 16)
A) 0.952 g
B) 3.816 g
C) 3.782 g
D) 8.64 g
Explanation
(b)
$CuSO_{4}$ $5H_{2}O$ has 1 mole of copper and 9 moles of oxygen atoms,
$63.5\ g\ Cu = 9 \times 16\ g$ of oxygen
$8.64\ g\$of oxygen $= \frac{63.5 \times 8.64}{9 \times 16}$
$= 3.81g$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.