Now we can use the molar mass of NH3 to find the mass produced.

2.677 mol NH3 * 17.03052 g / mol NH3 = 45.596 g NH3 produced

Finally you can calculated the volume assuming STP (P = 1 atm and T = 273 K). If you recall that 1 mole of gas at STP occupies 22.4 L. You could also do this using the ideal gas law with the above temperature and pressure as well as the number of moles from above.

2.677 mol NH3 * 22.4 L / mol = 59.965 L of NH3.

If you were given other details about the temperature and pressure, then you would have to use the ideal gas law (PV = nRT)

Any additional questions about this problem please ask.