PLEASE HELP!! I have to pass this class! Anything!!

We'll have 8.0 moles Fe3O4 and 4.0 moles CO2

Explanation:

Step 1: data given

Number of moles Fe2O3 = 12.0 moles

Number of moles CO = 12.0 moles

Step 2: The balanced equation

3Fe2O3 +CO → 2Fe3O4 + CO2

Step 3: Calculate the limiting reactant

For 3 moles Fe2O3 we need 1 mol CO to produce 2 moles Fe3O4 and 1 mol CO2

Fe2O3 is the limiting reactant. It will completely be consumed (12.0 moles).

CO is in excess. There will react 12.0 / 3 = 4.0 moles

There will remain 12.0 - 4.0 = 8.0 moles

Step 4: Calculate moles products

For 3 moles Fe2O3 we need 1 mol CO to produce 2 moles Fe3O4 and 1 mol CO2

For 12.0 moles Fe2O3 we'll have 2/3 * 12.0 = 8.0 moles Fe3O4

For 12.0 moles Fe2O3 we'll have 12.0 / 3 = 4.0 moles CO2

We'll have 8.0 moles Fe3O4 and 4.0 moles CO2

the answer is barium and copper bromide

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.