The Molar Mass of NH3
Ammonia (NH3) is a compound made up of one nitrogen atom and three hydrogen atoms. To determine how many molecules are in 5.00 grams of NH3, we first need to calculate the molar mass of NH3. The molar mass is the mass of one mole of a substance and is expressed in grams per mole (g/mol).
The molar mass of NH3 can be calculated by adding the atomic masses of each element present in the compound. The atomic mass of nitrogen (N) is approximately 14.01 g/mol, and the atomic mass of hydrogen (H) is approximately 1.01 g/mol. Therefore, the molar mass of NH3 is calculated as:
Molar mass of NH3 = 1(N) + 3(H) = 1(14.01 g/mol) + 3(1.01 g/mol) = 14.01 g/mol + 3.03 g/mol = 17.04 g/mol
Calculating the Number of Moles in 5.00 Grams of NH3
Now that we have determined the molar mass of NH3, we can use it to calculate the number of moles present in 5.00 grams of NH3. The relationship between mass, moles, and molar mass is given by the formula:
Number of moles = Mass / Molar mass
Substituting the given values into the formula:
Number of moles = 5.00 g / 17.04 g/mol ≈ 0.293 moles
Converting Moles to Molecules
Once we have determined the number of moles of NH3 in 5.00 grams, we can now calculate the number of molecules. To convert moles to molecules, we use Avogadro’s number, which is defined as the number of particles in one mole of a substance. Avogadro’s number is approximately 6.022 x 10^23 molecules/mol.
The formula for converting moles to molecules is given as:
Number of molecules = Number of moles x Avogadro’s number
Substituting the values into the formula:
Number of molecules = 0.293 moles x 6.022 x 10^23 molecules/mol ≈ 1.76 x 10^23 molecules
Summary:
- The molar mass of NH3 is 17.04 g/mol.
- 5.00 grams of NH3 is equivalent to approximately 0.293 moles.
- There are approximately 1.76 x 10^23 molecules in 5.00 grams of NH3.
In conclusion, the number of molecules in 5.00 grams of NH3 can be calculated by first determining the number of moles using the molar mass of the compound. By converting moles to molecules using Avogadro’s number, we find that there are approximately 1.76 x 10^23 molecules in 5.00 grams of NH3.
