HELP !! Given the balanced chemical equation:

4 Fe + 3 O2 > 2 Fe2O3

How many moles of iron(III) oxide, Fe2O3 , will be produced if 12 moles of oxygen gas, O2 , are consumed

8 moles of Fe2O3

Explanation:

You can use the mole ratio give. For every 3 O2 you produce 2 Fe2O3. With this you can find the number of moles. 12 O2 multiplied by the ratio 2/3 gives you 8 moles

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