We have to find the number of moles that there are in 119 g of NH₃, To find the number of moles of any compound in a determined mass of it we have to use the molar mass. The molar mass is the mass of one mol of any compound. So, let's find the molar mass of NH₃.
To find the molar mass of NH₃ we have to look for the atomic masses of its elements.
N: 14.01 amu
H: 1.01 amu
Then the molar mass is:
molar mass of NH₃ = 1 * 14.01 + 3 * 1.01
molar mass of NH₃ = 17.04 g/mol
Now that we know the mass of one mol of NH₃ we can find the number of moles of NH₃ that there are in 119 g of it.
number of moles = 119 g of NH₃ * 1 mol of NH₃/17.04 g
number of moles = 6.98 moles of NH₃
Answer: there are 6.98 moles of NH₃ in 119 g of it.