Nitrogen reacts with oxygen gas to form 110 grams of nitrogen dioxide.calculate the mass of oxygen gas and nitrogen took place in reaction
Answers
Nitrogen will be your excess reactant.
Start with the balanced chemical equation for your reaction
http://www.bbc.co.uk/schools/gcsebitesize/science/21c/air_quality/chemical_reactionsrev5.shtml
http://www.bbc.co.uk/schools/gcsebitesize/science/21c/air_quality/chemical_reactionsrev5.shtml
N
2
(
g
)
+
2
O
2
(
g
)
→
2
N
O
2
(
g
)
Notice that you have a
1
:
2
mole ratio between nitrogen and oxygen. This means that, regardless of how many moles of nitrogen react, you'll need twice as many moles of oxygen for the reaction to take place.
Since all the gases are at the same pressure and temperature, you can write
P
V
nitrogen
=
n
nitrogen
⋅
R
T
, and
P
V
oxygen
=
n
oxygen
⋅
R
T
You can isolate the constant terms on one side of the equation to get
P
R
T
=
n
nitrogen
V
nitrogen
and
P
R
T
=
n
oxygen
V
oxygen
This means that, when the gases are at the same pressure and temperature, the mole ratio becomes the volume ratio.
n
nitrogen
V
nitrogen
=
n
oxygen
V
oxygen
⇒
n
nitrogen
n
oxygen
=
V
nitrogen
V
oxygen
So, regardless of how many liters of nitrogen react, you need twice as many liters of oxygen for the reaction to take place. In order for all the nitrogen to react, you would need
10
liters
N
2
⋅
2
liters
O
2
1
liter
N
2
=
20 L
O
2
SInce you only have 10 L of oxygen, all the oxygen will be consumed and you'll be left with excess nitrogen. The reaction will only consume
10
liters
O
2
⋅
1 liter
N
2
2
liters
O
2
=
5 L
N
2
Therefore, you'll be left with
V
nitrogen excess
=
10
−
5
=
5 L