Sodium azide is used in automobile airbags to provide a source of nitrogen gas for rapid inflation in an accident - HSC - SSCE Chemistry - Question 19 - 2010 - Paper 1
Question 19
Sodium azide is used in automobile airbags to provide a source of nitrogen gas for rapid inflation in an accident. The equation shows the production of nitrogen gas ... show full transcript
Worked Solution & Example Answer:Sodium azide is used in automobile airbags to provide a source of nitrogen gas for rapid inflation in an accident - HSC - SSCE Chemistry - Question 19 - 2010 - Paper 1
Step 1
Calculate the number of moles of N2 gas required for 40 L at 100 kPa and 0°C
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Answer
Using the Ideal Gas Law, PV = nRT:
Where:
P = 100 kPa = 100,000 Pa
V = 40 L = 0.040 m³
R = 8.314 J/(K·mol)
T = 0°C = 273.15 K
Rearranging the equation to find n:
n=RTPV
Substituting the values in:
n=(8.314)(273.15)(100000)(0.040)
Calculating:
n≈1.78extmolesofN2
Step 2
Determine the moles of NaN3 needed
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Answer
From the balanced equation, 2 moles of NaN3 produce 3 moles of N2.
Using the ratio:
nNaN3=nN2×32
Substituting the value of moles of N2:
nNaN3=1.78×32≈1.19extmolesofNaN3
Step 3
Calculate the mass of sodium azide required
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Answer
The molar mass of NaN3 is:
Na: 22.99 g/mol
N: 14.01 g/mol
Thus, the molar mass of NaN3:
MNaN3=22.99+(3×14.01)=65.02extg/mol
Now, calculating the mass:
mass=n×MNaN3
Substituting the moles of NaN3:
mass=1.19×65.02≈77.4extg
Therefore, rounding up, the closest answer is 76 g.
