Chemistry please help!?
2018-04-04 11:33 pm
A sample of mercury (II) oxide is placed in a 5.00 L evacuated container and heated until it decomposes entirely to mercury metal and oxygen gas. The container is then cooled to 25 degrees Celsius. One now finds that the gas pressure inside the container is 1.73 atm. What mass of mercury (II) oxide was originally placed into the container? I keep coming king up with 76.6 g but the correct answer is supposed to be 153g and I don't know where I went wrong?
回答 (1)
2018-04-05 12:16 am
2HgO(s) → 2Hg(l) + O₂(g)
Mole ratio HgO : O₂ = 2 : 1
Consider the O₂ formed:
Pressure, P = 1.73 atm
Volume, V = 5.00 L
Gas constant, R = 0.08206 L atm / (mol K)
Temperature, T = (273 + 25) K = 298 K
Gas law: PV = nRT
No. of moles of O₂ produced, n = PV/(RT) = 1.73 × 5.00 / (0.08206 × 298) mol = 0.354 mol
No. of moles of HgO = (0.354 mol) × 2 = 0.708 mol
Molar mass of HgO = (200.6 + 16.0) g/mol = 216.6 g/mol
Mass of HgO = (0.708 mol) × (216.6 g/mol) = 153 g
Mole ratio HgO : O₂ = 2 : 1
Consider the O₂ formed:
Pressure, P = 1.73 atm
Volume, V = 5.00 L
Gas constant, R = 0.08206 L atm / (mol K)
Temperature, T = (273 + 25) K = 298 K
Gas law: PV = nRT
No. of moles of O₂ produced, n = PV/(RT) = 1.73 × 5.00 / (0.08206 × 298) mol = 0.354 mol
No. of moles of HgO = (0.354 mol) × 2 = 0.708 mol
Molar mass of HgO = (200.6 + 16.0) g/mol = 216.6 g/mol
Mass of HgO = (0.708 mol) × (216.6 g/mol) = 153 g
收錄日期: 2021-04-24 01:01:40
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20180404153318AA9Xodg