What mass of co is needed to react completely with55.0 g of fe2o3(s)+co(g) yield fe(s)+co2(g)?

28.9 g

Explanation:

We know that we will need a balanced equation with masses, moles, and molar masses of the compounds involved.  

Gather all the information in one place with molar masses above the formulas and masses below them.  

:     159.69    28.01

              Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂

Mass/g:  55.0

1. Use the molar mass of Fe₂O₃ to calculate the moles of Fe₂O₃.

2. Use the molar ratio of CO:Fe₂O₃ to calculate the moles of CO.

3.Use the molar mass of CO to calculate the mass of CO.

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol