Avogadro's law: When half a liter of carbon dioxide gas is passed over red coke, a reducing agent, the volume becomes `700 mL`. Assuming that volumes are measured at the same temperature and pressure, find the composition of product.
Strategy: The term composition indicates that we are dealing with a mixture. Write the correct balanced equation and use volume in place in moles.

Explanation

`{:(,CO_(2)(g)+C(s)rarr,2CO_(g)),(,1 "mol",2 "mol"),("At same T,P",1 "volume",2 "volumes"):}`
If `CO_(2)` is reduced completely the volume of `CO` produced should be `1000 mL`. Since we get just `700 mL`, it only means that `CO_(2)` gas it not reduced completley. Assuming that `X` milliters of `CO_(2)` is reduced, we get `2X` militers of `CO`.
Now, `V_(CO_(2)) + V_(CO) = 700 mL`
`(500-X)mL + 2X mLO = 700 mL`
`:. X = 200 mL`
Thus, `700 mL` contains `300 mL, CO_(2)` and `400 mL CO`.