Question

compound which contains 80% carbon of mass is​

Answer 1

Answer:

We have ethane.

Explanation:

As with all these problems, it is usually assumed that we have a 100⋅g mass of unknown compound, and we work out the molar quantities:

And thus moles of carbon≡80⋅g12.011⋅g⋅mol−1=6.66⋅mol.

And thus moles of hydrogen≡20⋅g1.008⋅g⋅mol−1=19.8⋅mol.

We divide the molar quantities thru by the SMALLER molar quantity:

C:6.66⋅mol6.66⋅mol=1

H:19.8⋅mol6.66⋅mol=2.97

And thus the empirical formula = CH3

And we know that the molecular formula is always a multiple of the empirical formula, and thus is terms of mass:

i.e. molecular formula = n×empirical formula

But we have a molecular mass of 30⋅amu

So 30⋅amu = n×(12.01+3×1.01)⋅amu

Clearly, n=2, and the MOLECULAR FORMULA is C2H6.

This is not a realistic problem, as few analysts would perform combustion on a liquid, and no analyst could perform combustion on a gas.

Answer 2

Answer:

compound which contains 80% carbon of mass is ethane.

hope it helps u...