Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Calcium Nitrate Tetrahydrate 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 Calcium Nitrate Tetrahydrate 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, pH of a 5% Solution at 25.0 °C, Insoluble Matter, Chloride, Nitrite, Sulfate, Barium, Heavy Metals, Iron, Magnesium, Potassium, Sodium, and Strontium.
Ca(NO3)2·4H2O
Formula Wt 236.15
CAS No. 13477-34-4
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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colorless, hygroscopic solid preparation of calcium standard solutions melting point,42 °C 66 g in 100 mL at 30 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.0–103.0% Ca(NO3)2 · 4H2O pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 5.0–7.0
Insoluble matter . . . . . . . Chloride (Cl) . . . . . . . . . Nitrite (NO2) . . . . . . . . . Sulfate (SO4) . . . . . . . . . Barium (Ba) . . . . . . . . . . Heavy metals (by ICP–OES) Iron (Fe) . . . . . . . . . . . .
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© 2017 American Chemical Society
Maximum Allowable 0.005% 0.005% 0.001% 0.002% 0.005% 5 ppm 5 ppm
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DOI:10.1021/acsreagents.4082 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Magnesium (Mg) Potassium (K) . . Sodium (Na) . . . Strontium (Sr) .
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0.05% 0.005% 0.01% 0.05%
TESTS Assay (By complexometric titration of calcium). Weigh accurately about 0.90 g, transfer to a 250 mL beaker, and dissolve in 150 mL of water. While stirring, add from a 50 mL burette about 30 mL of 0.1 M EDTA volumetric solution. Then adjust the solution to above pH 12 with 10% sodium hydroxide reagent solution. Add about 300 mg of hydroxynaphthol blue indicator mixture, and continue the titration immediately with 0.1 M EDTA to a blue color. One milliliter of 0.1 M EDTA corresponds to 0.02362 g of Ca(NO3)2 · 4H2O.
pH of a 5% Solution at 25.0 °C [Part 2: Direct Electrometric Methods; pH Potentiometry; pH Range; Procedure for pH of a 5% Solution at 25.0 °C].
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Dissolve 20 g in 200 mL of water.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Dissolve 1.0 g in 50 mL of water, and dilute 10 mL of the solution with water to 20 mL.
Nitrite [Part 2: Direct Electrometric Methods; Specific Polarographic Procedures; Polarographic Procedure for Nitrate]. Use 1.0 g of sample and 0.01 mg of nitrite.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 2]. Use 6 mL of hydrochloric acid.
Barium For the sample, dissolve 2.0 g in 15 mL of water, add 2 g of sodium acetate and 0.05 mL of glacial acetic acid, and filter if necessary. For the standard, add 0.1 mg of barium to 15 mL of water, then add 2 g of sodium acetate and 0.05 mL of glacial acetic acid. Add to each solution 2 mL of 10% potassium dichromate reagent solution, mix, and let stand for 15 min. Any turbidity in the solution of the sample should not exceed that in the standard.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4082 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Heavy Metals ([Part 2: Trace and Ultratrace Elemental Analysis; Inductively Coupled Plasma−Optical Emission Spectroscopy (ICP–OES); Calculation of Heavy Metals (by ICP–OES) Results], by ICP–OES). Use 2.0 g sample..
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Use 2.0 g.
Magnesium, Potassium, Sodium, and Strontium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Magnesium, Potassium, Sodium, and Strontium
S a m p l e S t o c k S o l u t i o n . Dissolve 4.0 g of sample in 80 mL of water. Transfer to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.04 g).
For the Determination of Magnesium, Potassium, Sodium, and Strontium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Mg
285.2
0.02
0.01; 0.02
A/A
Yes
K
766.5
0.20
0.01; 0.02
A/A
No
Na
589.0
0.10
0.01; 0.02
A/A
No
Sr
460.7
0.20
0.10; 0.20
N/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4082 ACS Reagent Chemicals, Part 4
