The number of atoms present in 4.25 g of NH3 is approximately.

Sure, here are the steps to find the number of atoms in 4.25 g of NH3:

1. First, we need to find the molar mass of NH3. The atomic mass of Nitrogen (N) is approximately 14 g/mol and Hydrogen (H) is approximately 1 g/mol. Since NH3 has one Nitrogen atom and three Hydrogen atoms, the molar mass of NH3 is 14g/mol + 3(1g/mol) = 17 g/mol.

2. Next, we need to find the number of moles in 4.25 g of NH3. We can use the formula: number of moles = mass / molar mass. So, the number of moles in 4.25 g of NH3 is 4.25 g / 17 g/mol = 0.25 mol.

3. Now, we can find the number of molecules in 0.25 mol of NH3. We use Avogadro's number (6.022 x 10^23), which is the number of molecules in one mole. So, the number of molecules in 0.25 mol is 0.25 mol x 6.022 x 10^23 molecules/mol = 1.5055 x 10^23 molecules.

4. Finally, since each molecule of NH3 contains 4 atoms (1 Nitrogen and 3 Hydrogen), the total number of atoms in 4.25 g of NH3 is 1.5055 x 10^23 molecules x 4 atoms/molecule = 6.022 x 10^23 atoms.

So, there are approximately 6.022 x 10^23 atoms in 4.25 g of NH3.