Question

A solution contains A13+ and Co2+. The addition of 0.3721 L of 1.733 M NaOH results in the complete precipitation of the ions as Al(OH), and Co(OH),. The total mass of the precipitate is 22.85 g. Find the masses of A13+ and Co2+ in the solution. mass of A18+: ban mass of Co2+: 09

Answer 1

LLLLLL | 6:31R1 2 , 6 |-133 M N • H moles = molarity & volume a moles of NaOH = 0.3727% 1.7335 0645 moles mass of precipitate (ALCOH + Co (02) = 22-85 on let mass of Allohl3 = regma mass of ColoHla= (22-85-2e)ym molar mass of pe lo hlz = 78 g/mol s moles of Al 10Hz = 2 . Aldolla - Al3+ + 3oh a moles of oi = 3 males of allolz= 3x molar mass of Coco Hl2 = 93 olmal a moles of colotle = 22-85-22 . 93 - Colohla (02t + 2at a males of o* = 2*62205 - 2) = 453 a males of on= 2-85-2 457-222 93 1. 93 from es do , dii & ibi moles of ot" from noole = modes of of in precipitate 0.645 = 32 Et et 45-7-22e 93 a ze= 9.06 a mass of Allo Hi3 = 2 = good gm . : mass of CocoHl2 = 22-85-= 13.79 gm a moles of Allo H)3= 20 = 0.116 amal moles of CO(OH)2 = aardse s 0.148 mol - 16 19 Allottiz Al3+ CScanned With camoles of Al3+ = + 3.4 0+116 mol

27ormal molar mass of Al3+ a mass of me 37 = 27X0-116 = 3•13 om answer Cocoll2 - co2t + 20H a moles of co2t = 0.148 mal 1 molar mass of colt = so glmel mass of Al co2t = 59x0+148 = 8073gm lan angwe CScanned with CamScanner