<u>Answer:</u> The molar mass of the given unknown compound is 50.5 g/mol.
<u>Explanation:</u>
To calculate the volume of water, we use the equation given by ideal gas, which is:

or,

where,
P = pressure of sample = 1.00 atm
V = volume of sample = 2010 mL = 2.010 L (Conversion factor: 1 L = 1000 mL)
m = Given mass of unknown compound = 2.73 g
M = Molar mass of unknown compound = ? g/mol
R = Gas constant = 
T = temperature of sample = ![180^oC=[180+273]K=453K](https://tex.z-dn.net/?f=180%5EoC%3D%5B180%2B273%5DK%3D453K)
Putting values in above equation, we get:

Rounding off to 3 significant figures, we get the molar mass to be 50.5 g/mol.
Hence, the molar mass of the given unknown compound is 50.5 g/mol.