<u>Answer:</u> The mass of nitrogen gas present in the given sample is 0.037 g
<u>Explanation:</u>
To calculate the number of moles, we use the equation given by ideal gas equation:

Or,

where,
P = Pressure of the gas = 688 mmHg
V = Volume of gas = 100 mL = 0.1 L (Conversion factor: 1 L = 1000 mL)
m = Mass of nitrogen gas = ?
M = Molar mass of nitrogen gas = 28 g/mol
R = Gas constant = 
T = Temperature of the gas = ![565^oC=[565+273]=838K](https://tex.z-dn.net/?f=565%5EoC%3D%5B565%2B273%5D%3D838K)
Putting values in above equation, we get:

Hence, the mass of nitrogen gas present in the given sample is 0.037 g