Question

What molar quantity of carbon dioxide will result, if a six mole quantity of pentane are completely combusted?

Answer 1

Approx. `30*mol` of carbon dioxide will evolve from combustion.

Explanation:

For all problems of this kind, our starting point is a stoichiometrically balanced equation:

`C_5H_12(l) + 8O_2(g) rarr 5CO_2(g)+ 6H_2O(l)`

The equation is stoichiometrically balanced: `"garbage in equals garbage out"`.

It tells us unequivocally that if `72*g` of pentane react with stoichiometric, i.e. `256*g` of dioxygen, we are going to get `220*g` of carbon dioxide gas, and `108*g` of water vapour.

Here we start with, `5.79*mol` pentane, and thus `5xx5.79*mol` `CO_2` will evolve, all calculated on the basis of the given equation. What are (i) the mass of carbon dioxide, and (ii) the mass of water evolved from this quantity of pentane?