Answer
See the answer below.
Work Step by Step
The number of moles of $CO_2$ is given by:
$n=PV/RT$
$n=(44.8/760×1\ atm)×1.50\ L/((0.082)(298\ K))$
$n=0.00362\ mol$
This is also the number of moles of CO. Thus:
$0.00362\ mol×28.01\ g/mol=0.101\ g$
Mass of iron:
$0.142-0.101=0.041\ g$
Number of moles of iron:
$0.041\ g/55.845\ g/mol=0.000729\ mol$
Ratio: $0.00362/0.000729=4.96\approx 5$
Empirical formula:
$Fe(CO)_5$
