Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Cupric Sulfate Pentahydrate (Copper(II) Sulfate Pentahydrate)
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Part 4, Monographs for Reagent Chemicals: General Descriptions, Specifications, and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents
ABSTRACT This monograph for Cupric Sulfate Pentahydrate provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Insoluble Matter, Chloride, Nitrogen Compounds, Calcium, Iron, Nickel, Potassium, and Sodium.
CuSO4 · 5H2O
Formula Wt 249.68
CAS No. 7758-99-8
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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blue solid source of CuII ion melting point, 110 °C with loss of 4 water molecules 33 g in 100 mL at 20 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.0–102.0% CuSO4 · 5H2O Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Nitrogen compounds (as N) . . . . . . . . . . . . . . 0.002% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.003% Nickel (Ni) . . . . . . . . . . . . . . . . . . . . . . . . . 0.005% Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.02%
© 2017 American Chemical Society
A
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4108 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By iodometric titration of oxidative capacity of CuII). Weigh accurately about 1.0 g, dissolve in water, transfer to a conical flask, and dilute with water to about 50 mL. Add 4 mL of glacial acetic acid, 1 mL of 10% sulfuric acid, and 3 g of potassium iodide. Titrate the liberated iodine with 0.1 N sodium thiosulfate volumetric solution, adding about 2 g of potassium thiocyanate and 3 mL of starch indicator solution near the end of the titration. Correct for a blank. One milliliter of 0.1 N sodium thiosulfate corresponds to 0.02497 g of CuSO4 · 5H2O.
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Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 200 mL of dilute sulfuric acid (1:40). Omit heating.
Chloride Dissolve 1.0 g in 15 mL of water, filter if necessary through a small chloride-free filter, and add 1 mL of nitric acid and 1 mL of silver nitrate reagent solution. Any turbidity should not exceed that produced by 0.01 mg of chloride ion (Cl) in an equal volume of solution containing the quantities of reagents used in the test. The comparison is best made by the general method for chloride in colored solutions, [Part 2: Colorimetry and Turbidimetry; Chloride].
Nitrogen Compounds [Part 2: Colorimetry and Turbidimetry; Nitrogen Compounds: Test for Ammonia, Amines, and Nitrogen Compounds Reduced by Aluminum]. Use 1.0 g. For the standard, use 0.02 mg of nitrogen.
Calcium, Iron, Nickel, Potassium, and Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Iron, Nickel, Potassium, and Sodium
S a m p l e S t o c k S o l u t i o n . Dissolve 20.0 g of sample in water, and add 5 mL of nitric acid. Transfer to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.20 g).
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4108 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Calcium, Iron, Nickel, Potassium, and Sodium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
0.80
0.02; 0.04
N/A
No
Fe
248.3
4.0
0.12; 0.24
A/A
Yes
Ni
232.0
4.0
0.10; 0.20
A/A
Yes
K
766.5
0.40
0.02; 0.04
A/A
No
Na
589.0
0.05
0.005; 0.01
A/A
No
Downloaded by CORNELL UNIV on June 6, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4108
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
C
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4108 ACS Reagent Chemicals, Part 4
