Question

How many grams of NH3 are needed to provide the same number of molecules as in 0.35 g of SF6 ?

Answer 1

Answer:

• There are 0.041 g of NH₃ in the same number of molecules as in 0.35 g of SF₆.

Explanation:

Using the molar mass of the chemical formula SF₆ you can find the number of moles of molecules in 0.35 g of such substance. Then, using the molar mass of NH₃, you can find mass in grams corresponding to the same number of molecules.

1. Find the molar mass of SF₆:

Atom   atomic mass          number of atoms   total mass in 1 mole

S           32.065 g/mol                     1                                       32.065 g

F            18.998 g/mol                     6                 6 × 18.998 = 113.988 g

                                                                               =====================

                                                          molar mass of SF₆ =    146.053 g/mol

2. Find the number of moles in 0.35 g of SF₆:

• number of moles = mass in grams / molar mass

• number of moles = 0.35 g / 146.053 g / mol = 0.0024 mol

3. Find the molar mass of NH₃:

Atom   atomic mass          number of atoms   total mass 1 mole                

N           14.007 g/mol                     1                                       14.007 g

H             1.008 g/mol                    3               3 × 1.008 g = 113.988 g

                                                                               =====================

                                                         molar mass of NH₃ =    17.031 g/mol

4. Find the mass in 0.0024 mol of NH₃:

• mass in grams = number of moles × molar mass

• mass = 0.0024 mol × 17.031 g/mol ≈ 0.041 grams

5. Conclusion:

There are 0.041 g of NH₃ in the same number of molecules as in 0.35 g of SF₆.