Question

6. The petrol additive tetraethyl-lead(IV), Pb(C2H5)4, is now banned in many countries. When it is completely bumed in air, lead(II) oxide, CO and H2O are formed. How many moles of oxygen are required to burn one mole
of Pb(C2H5)4?
A 9.5
B 11
C 13.5
D 27

Answer 1

Answer:

9.5 mol

Explanation:

Let's consider the unbalanced equation for the combustion of tetraethyl-lead (IV).

Pb(C₂H₅)₄ + O₂ ⇒ PbO + CO + H₂O

Pb atoms are balanced. We will balance C atoms by multiplying CO by 8.

Pb(C₂H₅)₄ + O₂ ⇒ PbO + 8 CO + H₂O

Then, we will balance H atoms by multiplying H₂O by 10.

Pb(C₂H₅)₄ + O₂ ⇒ PbO + 8 CO + 10 H₂O

Finally, we get the balanced equation by multiplying O₂ by 9.5.

Pb(C₂H₅)₄ + 9.5 O₂ ⇒ PbO + 8 CO + 10 H₂O

All in all, we need 9.5 moles of O₂ to burn 1 mole of Pb(C₂H₅)₄.