# How calculate this ?

Aug 5, 2018

Would it not be $B$?

#### Explanation:

Look at your stoichiometry. All the reagents, reactants, and products, are in the gaseous state...

$2 C O \left(g\right) + {O}_{2} \left(g\right) \rightarrow 2 C {O}_{2} \left(g\right)$

And because under conditions of equivalent pressure and temperature, such as are invoked HERE....VOLUME is proportional to the number of moles (this is old Avogadro's gas law...${V}_{\text{volume of gas"propn_"moles of gaseous particles}}$

And your equation explicitly says, that TWO volumes of $C O$ react with ONE volume of dioxygen to give TWO VOLUME of $C {O}_{2}$. Capisce? The stoichiometry is there in front of you.

And so if have a $40 \cdot c {m}^{3}$ volume of $C O$ equivalence requires a $20 \cdot c {m}^{3}$ volume of ${O}_{2}$ to give a $40 \cdot c {m}^{3}$ volume of $C {O}_{2}$, the product.

All of this is an example of stoichiometry. When you make or receive change for a cash transaction I suspect that you are seldom short-changed. Why? Because you are trained from an early age to handle money, to assess stoichiometric equivalence. And we are doing precisely the same thing here...