An unknown mass of ammonium perchlorate,NH₄ClO₄ (117.5 g/mol),is placed in an evacuated 1.00 L flask and heated to 251°C.At this temperature the NH₄ClO₄ decomposes violently.The gaseous products exert a pressure of 466 mm Hg at 251°C.What mass of NH₄ClO₄ was placed in the flask? 2NH₄ClO₄(s)→ N₂(g)+ Cl₂(g)+ 2O₂(g)+ 4H₂O(g)

Question

Quizplus · Accepted Answer

First, we need to calculate the number of moles of the gaseous products formed using the ideal gas law: PV=nRT n=(PV)/(RT) n=(466 mmHg)(1 L)/(62.3637 L mmHg K)(524 K) n=0.0159 mol According to the stoichiometry of the reaction, 2 moles of NH₄ClO₄ produce 1 mole of N₂, 1 mole of Cl₂, 2 moles of O₂, and 4 moles of H₂O. Therefore, the number of moles of NH₄ClO₄ that were present in the flask is: n(NH₄ClO₄)=(0.0159 mol)/(2 mol) n(NH₄ClO₄)=0.00795 mol Finally, we can calculate the mass of NH₄ClO₄ using its molar mass: m(NH₄ClO₄)=(0.00795 mol)(117.5 g/mol) m(NH₄ClO₄)=0.935 g Therefore, the best choice is B) 0.419 g.

An Unknown Mass of Ammonium Perchlorate,NH4ClO4 (117

An Unknown Mass of Ammonium Perchlorate,NH₄ClO₄ (117