Other Chemistry Answers

A water was tested for water hardness. A 50.00 mL aliquot was prepared and buffered to pH 10.0, it required 23.55 mL of 0.0250 M EDTA. A second aliquot, prepared with NaOH, was titrated with 14.53 mL of the same EDTA titrant. Calculate the following:

a. total hardness (in ppm CaCO3)

b. magnesium hardness (in ppm MgCO3)

1. For the following reaction at 25 ^oC, under these conditions: [Fe²⁺] = 0.50 M, [Fe³⁺] = 0.10 M, [MnO₄⁻] = 0.025 M, [Mn²⁺] = 0.015 M, and a pH of 7.00.

5Fe²⁺(aq) + MnO₄⁻(aq) + 8H⁺(aq) ⇌ 5Fe³⁺(aq) + Mn²⁺(aq) + 4H₂O(l)

Calculate

(a) the standard potential

(b) the equilibrium constant

(c) the potential 

 A 25.ID-mL sample containing Fe³° and Cu°° required

16.06 mL of 0.050 83 M EDTA for complete titration. A 50.IXI-mL sample of the unknown was treated 

with NH F to protect the Fe°°. Then Cu²° was reduced and masked by thiourea. Addition of

25.00 mL of 0.050 83 M EDTA liberated Fe  from its fluoride complex to form an EDTA complex. The 

excess EDTA required

19.77 mL of 0.018 83 M Pb'+ to reach a xylenol orange end point.

Find (Cu' ) in the unknown.

 A 10.231-9 sample of window cleaner containing amnmnia was diluted with 39.466 g of water. 

Then 4.373 g of solution were iitraied with 14.22 mL of 0.106 3 M HCI to reach a bromocresol green 

end point. Find the weight percent of NH (FM 17.031) in the cleaner.

Ni(CNi42 + 2AgBr(i)  2Ag(C 2 + Ni²+ + 2Br°

The liberated nickel ion required 26.73 mL of 0.02089 M EDTA. The bromate in a 10.00-mL aliquot was 

reduced to bromide with arsenic(UI) priof to the addition of silver nitrate. The same procedure 

was followed, and the released nickel ion was titrated with 21.94 mL of the EDTA solution. 

Calculate the percentages of NaBr and NaBrO3 in the sample.