Answer:
E
Explanation:
So this question tests your understanding of mole:mole ratios.
So looking at the equation we see for every 3 O2 there's 4 NH3, we can even word it like for every 4 mol of NH3 that reacts you need 3 moles of O2. This gives us the mole:mole (mole to mole) ratio of 3 mol O2/ 4 mol NH3.
Now since you have 3.5 moles of NH3 you can use the ratio from above to convert it to O2 by simply 3.5molNH3 * 3mol O2/4mol NH3 ------> 2.625mol O2
