You're asking about the number of moles in 0.75 what of ammonia? To calculate moles, we need to know the mass or volume of ammonia you have. Here's how to approach it:

1. If you have the mass of ammonia:

* Find the molar mass of ammonia (NH₃):

* Nitrogen (N) has a molar mass of 14.01 g/mol.

* Hydrogen (H) has a molar mass of 1.01 g/mol.

* Total molar mass of NH₃ = 14.01 + (3 * 1.01) = 17.04 g/mol

* Divide the mass of ammonia by its molar mass:

* Moles of ammonia = (mass of ammonia in grams) / (17.04 g/mol)

2. If you have the volume of ammonia (as a gas):

* You need to know the temperature and pressure of the ammonia gas.

* Use the Ideal Gas Law: PV = nRT

* P = pressure (in atm)

* V = volume (in liters)

* n = number of moles

* R = Ideal Gas Constant (0.0821 L·atm/mol·K)

* T = temperature (in Kelvin)

* Rearrange the equation to solve for n (number of moles):

* n = (PV) / (RT)

Example:

Let's say you have 0.75 grams of ammonia.

* Moles of ammonia = (0.75 g) / (17.04 g/mol) ≈ 0.044 moles

Please provide the mass or volume of ammonia, and I can calculate the number of moles for you.