Question

What effect would an incomplete decomposition of KCLO3 have on an experimentally determined molar mass? Explain using the ideal gas law

Answer 1

ideal gas law is

PV = nRT

n = PV / RT

n = number of moles of O2

decomposition reaction is

2 KClO3 .............> 2 KCl + 3 O2

During incomplete decomposition, number of moles of O2 obtained is less.

Hence

moles of KClO3 theoretically less than expected.

we know,

moles = mass / molar mass

or

molar mass = mass / moles.

as moles of KClO3 is less and hence experimentally determined molar mass should be decrease or less than expected.