Explanation:

1)Mass of CO when 210.3 g of Fe produced.
Number of moles of
in 210.3 g=


According to reaction, 2 moles of Fe are obtained from 3 moles of CO, then 3.76 moles of Fe will be obtained from :
of CO that is 5.64 moles.
Mass of CO in 5.64 moles =

2)Mass of CO when 209.7 g of Fe produced.
Number of moles of
in 209.7 g=


According to reaction, 2 moles of Fe are obtained from 3 moles of CO, then 3.75 moles of Fe will be obtained from :
of CO that is 5.625 moles.
Mass of CO in 5.625 moles =

Using the Fundamental Equation of Calorimetry, we have:
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C because it is and I know