) Which of the above (a,b,c,d,e) are also redox reactions? These problems are to
ID: 542705 • Letter: #
Question
) Which of the above (a,b,c,d,e) are also redox reactions? These problems are to be submitted next week, but you should work on them today with your group. 4.30 pts) Complete the following table: Work must be shown! Solution # Solute Mass of solute Volume of Molarity solution (L) (moles/iter) KNO3 CH3COONa NaOH 0.750 1034.43 0.100 0.0500 0.847 0.250 5.(12pts) Assuming additivity of volumes, what is the concentration, in moles/L, of a NaBr solution prepared by mixing 3.0 x 102 mL of 0.0625 M NaBr with 5.00 x 10 mL of 0.0250 M NaBr? Optional Bonus Problem (5pts)No partial credit A mixture containing only KBr and NaBr and weighing 0.765g was treated with Ag (aq). All the Br (aq) was recovered as 1.23 g of pure AgBr(s): Ag (aq) +Br(aq) ->AgBr(s) What is the percent by mass of KBr in the original sample?Explanation / Answer
No of mole of AgBr formed = w/mwt = 1.23/187.77 = 0.00655 mol
No of mole of Br- present in sample = 0.00655 mol
mass of Br- in sample = 0.00655*80 = 0.524 g
as 1 mol NaBr = 1 mol Br-
and 1 mol KBr = 1 mol Br-
NaBr = x mol , KBr = 0.00655 -x mol
0.765 = (x*103)+((0.00655-x)*119)
x = 0.000903 mol
mass of NaBr = x*103
= 0.000903*103
= 0.093 g
mass of KBr = 0.765-0.093 = 0.672 g
percent by mass of KBr = 0.672/0.765*100 = 87.84%
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.