1. Find the molar mass of tungsten:

* The molar mass of tungsten (W) is approximately 183.84 g/mol. This means that one mole of tungsten weighs 183.84 grams.

2. Multiply the molar mass by the number of moles:

* Mass = (Molar mass) x (Number of moles)

* Mass = (183.84 g/mol) x (15 mol)

* Mass = 2757.6 g

Therefore, the mass of 15 moles of tungsten is approximately 2757.6 grams.