Calculate pFe2+ at Ve in the titration of 25.00 mL of 0.02026 M EDTA by 0.03855 M Fe2+ at pH
A sample contained Ni and Zn ions as the only metals that would bind to EDTA. A 50.0 mL
solution of Ni2+ and Zn2+ was treated with 25.0 mL of 0.0452 M EDTA to bind all of the metal.
The excess unreacted EDTA required 12.4 mL of 0.0123 M Mg2+ for complete reaction. An excess
of the reagent 2,3-dimercapto-1-propanol was then added to the solution to displace the EDTA that
was bound to zinc. Another 29.2 mL of 0.0123 Mg2+ was required for reaction of the EDTA that
had been liberated from zinc. Calculate the molarity of Ni2+ and the molarity of Zn2+ in the original
Consider the EDTA titration below:
Zn2+ + Y4- ↔ ZnY2- Kf = 3.2×1016
a.) How many mL of 0.1050 M EDTA solution are required to reach the equivalence point in
the titration of 20.00 mL of 0.1433 M Zn2+, buffered at pH 10.00? (αY4- = 0.30 at pH 10.00)
b.) What is the pZn at the equivalence point?
c.) How many mL of EDTA solution would have been needed if the analyte solution was 20.00
mL of 0.1433 M Fe3+ instead of 20.00 mL of 0.1433 M Zn2+?
A 50.0 mL sample containing Ni2+ was treated with 25.0 mL of 0.0500 M EDTA and buffered at
pH 10.00. The excess EDTA was then back-titrated, requiring 5.00 mL of 0.0518 M Zn2+. What
was the concentration of Ni2+ in the original solution?
(At pH 10.00 αY4- = 0.30. KNiY = 2.5×1018. KZnY = 3.2×1016)
The initial mmole of 0.5065 for Fe+2 is based on the initial ...
The expert examines quant titrations calculations.
Quantitative Analysis in Chemistry
I have attached a paper with two questions I am not sure how to approach. This is my first assignment in quantitative analysis. I would like to start off with a good understanding of the topic, so complete work and explanation would be greatly appreciated.
Five mineral samples of equal mass of Calcite, 〖CaCO〗_3 (MM 100.085) had a total mass of 10.1 ± 0.1g. What is the average mass of calcium in each sample? (Assume that the relative uncertainties in atomic mass are small compared the uncertainty of the total mass.)
2. A solution of HNO3 is standardized by reaction with pure sodium carbonate.
2H+ + 〖Na〗_2 〖CO〗_3→ 2Na+ +H2O + 〖CO〗_2
A volume of 25.77 ± 0.06 mL of 〖HNO〗_3 solution was required for complete reaction with 0.8896 ± 0.0007g of Na2CO3, (FM 105.988 ± 0.001). Find the molarity of the 〖HNO〗_3 and its absolute uncertainty.