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 =
Answer: 26.54 grams
Explanation:
To calculate the moles :
is the limiting reagent as it limits the formation of product and 
is the excess reagent
According to stoichiometry :
As 1 moles of give = 3 moles of 
Thus 0.369 moles of 
give =
of
Mass of 
Thus 26.54 g of will be produced from the given mass.
The quantity that you would measure in kg, is mass.
The chemical reaction would be expressed as follows:
HBr + LiOH = LiBr + H2O
We are given the volumes and corresponding concentration to be used for the reaction. We use these values to solve for the concentration of the other reactant. We do as follows:
0.253 mol LiOH / L solution ( 0.01673 L ) ( 1 mol HBr / 1 mol LiOH ) = 0.00423 HBr needed
Concentration of HBr =0.00423mol / .010 L = 0.423 M HBr
