Consider the following, balanced reaction: 4 NH 3 ( g ) + 5 O 2 ( g ) --> 4 NO(
ID: 1002574 • Letter: C
Question
Consider the following, balanced reaction:
4 NH3(g) + 5 O2(g) --> 4 NO(g) + 6 H2O(l)
Which of the following are TRUE? There may be more than one correct answer.
Select one or more:
The reaction shown has exactly 4 moles of NH3 and 5 moles of O2 present at the beginning of the reaction.
If 8 moles of NH3 are used up, then 10 moles of O2 are also used up.
If you have 4 moles of NH3 and 4 moles of O2, then O2 is the limiting reactant.
If you have 4 moles of NH3 and 4 moles of O2, then NH3 is the limiting reactant.
For every 1 mole NH3 used up, there is 1 mole NO created.
For every 5 grams of O2 that react, 6 grams of H2O are created.
Explanation / Answer
4 NH3(g) + 5 O2(g) --> 4 NO(g) + 6 H2O(l)
(i) The reaction shown has exactly 4 moles of NH3 and 5 moles of O2 present at the beginning of the reaction.
We can see in the balanced equation, that there are 4 mol of NH3, 5 mol of O2 in the reactant side. So, the statement is true.
(ii) If 8 moles of NH3 are used up, then 10 moles of O2 are also used up.
From equation, for 4 mol of NH3, 5 mol of O2 is used. If we double both the moles, then for 8 mol of NH3, 10 mol of O2 will be used. So, this statement is also true.
(iii) If you have 4 moles of NH3 and 4 moles of O2, then O2 is the limiting reactant.
From equation, for every 4 mol of NH3, 5 mol of O2 is used. But if 4 mol of O2 is there, then it means that O2 is limiting reactant and NH3 is in excess. So, this statement is also true.
(iv) If you have 4 moles of NH3 and 4 moles of O2, then NH3 is the limiting reactant.
From equation, for every 4 mol of NH3, 5 mol of O2 is used. But if 4 mol of O2 is there, then it means that O2 is limiting reactant and NH3 is in excess. So, this statement is also false.
(v) For every 1 mole NH3 used up, there is 1 mole NO created.
From equation, 4 mol of NH3 produces 4 mol of NO. So, 1 mol of NH3 will produce 1 mol of NO. This statement is true.
(vi) For every 5 grams of O2 that react, 6 grams of H2O are created.
From equation, 5 mol of O2 produces 6 mol of H2O.
Number of moles in 5 grams of O2 = Mass/molar mass of O2 = 5/32 = 0.156 mol
Number of moles in 6 grams of H2O = Mass/molar mass of H2O = 6/18 = 0.33 mol
If 5 mol of O2 produces 6 mol of H2O.
Then, 0.156 mol of O2 will produce H2O = (6/5)*0.156 = 0.187 mol
But given moles of H2O produced = 0.33
So, this statement is false.