Question

cs₂(1) + 3 o₂(g) → co₂(g) + 2 so₂(g)
what volume of o₂(g) is required to react with excess cs₂(1) to produce 4.0 l of co₂(g)? (assume all gases are measured at 0°c and 1 atm.)
a 12 l
b 22.4 l
c 1/3 × 22.4 l
d 3 × 22.4 l

Explanation:

Step1: Analyze the mole ratio from the balanced equation

From the balanced equation \(CS_{2}(l)+3O_{2}(g)\to CO_{2}(g)+2SO_{2}(g)\), the mole ratio of \(O_{2}\) to \(CO_{2}\) is \(n(O_{2}):n(CO_{2}) = 3:1\).

Step2: Use Avogadro's law (at constant \(T\) and \(P\), \(V\propto n\))

Since \(V\propto n\) (Avogadro's law, \(T = 273\ K\), \(P=1\ atm\)), the volume ratio \(V(O_{2}):V(CO_{2})=n(O_{2}):n(CO_{2})\). Given \(V(CO_{2}) = 4.0\ L\), then \(V(O_{2})=3\times V(CO_{2})\).

Answer:

A. 12 L