Question

3. Hydrogen can be made by reacting carbon with steam, giving CO2 as a by-product.

CO2 + 2H2
44
2
M₁ =
C + 2H₂O
18
12
Calculate the atom economy of making hydrogen via this process.
8-3%.
4. Iron is made in a blast furnace by reduction of iron (III) oxide with carbon monoxide:
Fe2O3 + 3CO ➜>> 2Fe + 3CO2
Calculate the atom economy of making iron this way.
46%

Answer 1

The atom economy is defined as the percentage of total mass of reactants that ends up as the desired product.

For the reaction of carbon with steam to produce hydrogen:

C + 2H2O → CO2 + 2H2

The total molar mass of the reactants is:

Mtotal = Mc + 2Mh2o = 12 + 2(18) = 48 g/mol

The molar mass of the desired product (H2) is:

Mh2 = 2(1) = 2 g/mol

The atom economy can be calculated as:

Atom economy = (2Mh2 / Mtotal) x 100% = (2/48) x 100% ≈ 4.17%

Therefore, the atom economy of making hydrogen via this process is approximately 4.17%.

For the reaction of iron (III) oxide with carbon monoxide to produce iron:

Fe2O3 + 3CO → 2Fe + 3CO2

The total molar mass of the reactants is:

Mtotal = 2Mfe2o3 + 3Mco = 2(160) + 3(28) = 404 g/mol

The molar mass of the desired product (Fe) is:

Mfe = 2(56) = 112 g/mol

The atom economy can be calculated as:

Atom economy = (2Mfe / Mtotal) x 100% = (2(56) / 404) x 100% ≈ 46.53%

Therefore, the atom economy of making iron via this process is approximately 46.53%.