1. What is the voltage for: Cu2+ + Zn(s) → Cu(s) + Zn2+ at 298 K if [Cu2+] = 0.15 M and [Zn2+] = 4.0 M? E°cell = 1.20 V.
2. A 25.0 mL of aliquot of a well-shaken and filtered sample of river water is pipetted into an evaporating dish. The sample was heated to dryness. Determine the TDS content, express (a) in ppt and; (b) ppm using the
following data:
• Mass of evaporating dish = 24.44 g
• Mass of water sample + evaporating dish = 49.44g
• Mass of dried sample + evaporating dish = 25.37 g
3. A 25.0 mL of aliquot of a well-shaken of river water is pipetted into an evaporating dish. The sample was heated to dryness. Determine (a) TS and (b) TSS and express in terms of ppm using the following data:
• Mass of evaporating dish = 25.25 g
• Mass of dried sample + evaporating dish = 28.14 g
4. Solve the missing data:
Sample volume (mL) = 250
Buret Reading, initial (mL) = 5.57
Buret Reading, final (mL) = 25.25
Volume of Na2S2O3 dispensed (mL) = ________
Average molar concentration of Na2S2O3 (mol/L) = 0.025
Moles of Na2S2O3 dispensed (mol) = __________
Moles of I3- reduced by S2O32- (mol) = __________
Moles of O2 (mol) = __________
Mass of O2 (mg) = ___________
Dissolved oxygen, ppm O2 (mg/L) = ___________
1 answer