Some Basic Concepts Of Chemistry Question 31
Question: If $ 3.01\times 10^{20} $ molecules are removed from 98 mg of $ H _2SO _4 $ then the number of moles of $ H _2SO _4 $ left are
Options:
A) $ 0.1\times {10^{-3}} $
B) $ 0.5\times {10^{-3}} $
C) $ 1.66\times {10^{-3}} $
D) $ 9.95\times {10^{-2}} $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Moles of $ H _2SO _4 $ in 98 mg of $ H _2SO _4 $ $ =\frac{1}{98}\times 0.098=0.001 $ Moles of $ H _2SO _4 $ removes $ =\frac{3.01\times 10^{20}}{6.02\times 10^{23}}=0.5\times {10^{-3}}=0.0005 $ Moles of $ H _2SO _4 $ left $ =0.001-0.0005=0.5\times {10^{-3}} $
