What volume of hydrogen will be produced if 100cm3 of ammonia is completely decomposed at constant temperature and pressure? The equation for the reaction i...
What volume of hydrogen will be produced if 100cm3 of ammonia is completely decomposed at constant temperature and pressure? The equation for the reaction is 2NH3(g) → N2(g) + 3H2(g)
Answer Details
From the balanced chemical equation, we know that 2 moles of NH3 will produce 3 moles of H2. Therefore, to calculate the volume of H2 produced, we need to first find the number of moles of NH3 in 100cm3: 1 mole of any gas at room temperature and pressure (RTP) occupies a volume of 24dm3 (24000cm3). Therefore, the number of moles of NH3 in 100cm3 can be calculated as follows: 100cm3 = 100/1000 = 0.1dm3 0.1dm3 of NH3 at RTP = 1/24 moles (since 24dm3 = 1 mole) Therefore, the number of moles of NH3 in 100cm3 = (1/24) x 0.1 = 0.00417 moles (to 3 significant figures) Since 2 moles of NH3 produce 3 moles of H2, we can calculate the number of moles of H2 produced as follows: Number of moles of H2 = (3/2) x 0.00417 = 0.00625 moles (to 3 significant figures) Finally, we can use the ideal gas law to calculate the volume of H2 produced: PV = nRT where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin. Since the temperature and pressure are constant, we can write: VH2 / nH2 = VNH3 / nNH3 where VH2 and nH2 are the volume and number of moles of H2, and VNH3 and nNH3 are the volume and number of moles of NH3. Substituting the values we have calculated: VH2 / 0.00625 = 0.1 / (1/24) VH2 = 0.00625 x (1/0.0417) x 24 = 150cm3 Therefore, the volume of hydrogen produced is 150cm3.