Answer:
Step-by-step explanation:
To solve this problem, we can use stoichiometry to determine the amount of hydrogen gas evolved from the given mass of ammonia (NH3) on decomposition.
The balanced chemical equation for the decomposition of ammonia is:
2 NH3 → N2 + 3 H2
From the equation, we see that 2 moles of ammonia produce 3 moles of hydrogen gas.
Given:
- Mass of NH3 = 0.28 g
- Mass of N2 produced = 0.25 g
Let's calculate the moles of NH3 and then determine the moles of hydrogen produced:
Molar mass of NH3 = 14.01 g/mol (N) + 3 * 1.01 g/mol (H) = 17.04 g/mol
Moles of NH3 = Mass / Molar mass = 0.28 g / 17.04 g/mol ≈ 0.0164 mol
From the balanced equation, we know that 2 moles of NH3 produce 3 moles of H2.
So, moles of H2 produced = (3/2) * Moles of NH3 = (3/2) * 0.0164 mol ≈ 0.0246 mol
Now, let's calculate the mass of hydrogen produced:
Molar mass of H2 = 2 g/mol
Mass of H2 = Moles of H2 * Molar mass = 0.0246 mol * 2 g/mol = 0.0492 g
The rest of the mass is due to nitrogen (N2):
Mass of N2 = Mass of NH3 - Mass of H2 = 0.28 g - 0.0492 g = 0.2308 g
Now we can calculate the volume of hydrogen gas at NTP (22.4 L for 2 g of hydrogen):
Volume of H2 = (Mass of H2 / 2 g) * 22.4 L = (0.0492 g / 2 g) * 22.4 L ≈ 0.5592 L
The volume of hydrogen gas evolved at NTP is approximately 0.5592 liters.