Ammonia contains 82.65% N and 17.65%hydrogen. If the law of constant proportions is true then calculate the mass of zinc required to give 10 gm of ammonia. Please I need a proper explaination.

To solve the problem of calculating the mass of zinc required to produce 10 grams of ammonia (NH₃), we first need to understand the composition of ammonia and the chemical reaction involved in its formation. Ammonia consists of nitrogen and hydrogen in a specific ratio, and we can use this information along with the law of constant proportions to find the answer.

Understanding the Composition of Ammonia

Ammonia is made up of nitrogen (N) and hydrogen (H) in the molecular formula NH₃. The percentages given in the question indicate that ammonia contains 82.65% nitrogen and 17.65% hydrogen by mass. To find the mass of each element in 10 grams of ammonia, we can use these percentages:

• Mass of Nitrogen: 10 g × 0.8265 = 8.265 g
• Mass of Hydrogen: 10 g × 0.1765 = 1.765 g

The Chemical Reaction for Ammonia Production

Ammonia can be produced from zinc (Zn) and nitric acid (HNO₃) through a chemical reaction. The balanced equation for this reaction is:

Zn + 2HNO₃ → Zn(NO₃)₂ + H₂ + NH₃

From this equation, we can see that one mole of zinc produces one mole of ammonia. To find out how much zinc is needed to produce 10 grams of ammonia, we need to calculate the number of moles of ammonia first.

Calculating Moles of Ammonia

The molar mass of ammonia (NH₃) can be calculated as follows:

• Molar mass of N = 14.01 g/mol
• Molar mass of H = 1.008 g/mol × 3 = 3.024 g/mol
• Total Molar Mass of NH₃ = 14.01 g/mol + 3.024 g/mol = 17.034 g/mol

Now, we can calculate the number of moles of ammonia in 10 grams:

Number of moles of NH₃ = Mass / Molar Mass = 10 g / 17.034 g/mol ≈ 0.587 moles

Determining the Mass of Zinc Required

Since the balanced equation shows that 1 mole of zinc produces 1 mole of ammonia, we need the same number of moles of zinc as the moles of ammonia produced. Therefore, we need approximately 0.587 moles of zinc.

The molar mass of zinc (Zn) is about 65.38 g/mol. Now we can calculate the mass of zinc required:

Mass of Zn = Number of moles × Molar mass = 0.587 moles × 65.38 g/mol ≈ 38.34 g

Final Calculation

To produce 10 grams of ammonia, approximately 38.34 grams of zinc is required. This calculation illustrates the application of the law of constant proportions, as the mass ratios remain consistent regardless of the amount of ammonia produced.

In summary, the mass of zinc needed to produce 10 grams of ammonia is about 38.34 grams, based on the stoichiometry of the reaction and the composition of ammonia.