Question

Kirsten is in her lab, and reacts two unknown gases (A(g) and B(g)) to get nitrogen dioxide (NO2). Using her data, she is able to write the following balanced equation:

2A(g) + B(g) --> 2NO2(g)
If she started with 8 L of A(g) and 3 L of B(g), how many liters of NO2(g) would she get? [Assume everything is at STP.]


2 L
3 L
4 L
6 L
8 L

Answer 1

When gases react to produce a gas, we need not go through the mol step; i.e., we can use liters as if liters were mols.
You can see this is a limiting reagent problem. It takes twice as much A as B; therefore, it would take 4 L of B to react with 8 L of A and we don't have 4 L of B. So I guessed wrong. 3 L of B will require 6 liters of A and we have more than enough. So B is the limiting reagent and all of B reacts. How much of the product will be formed? And you have your answer.