folletos sobre sustancias quimicas

8/7/2019 folletos sobre sustancias quimicas

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Answers to questions

about inorganic salts

that youve always

wanted to ask.

Answers to questions

about inorganic salts

that youve always

wanted to ask.


2/10

What oxidizing agents are included

in the range of inorganic salts?

First of all, peroxodisulfates, e.g.

Potassium peroxodisulfate GR for analysis

(Cat. No. 1.05091), or pure peroxide

Sodium peroxide granular GR for analysis,

ACS, ISO (Cat. No. 1.06563).

As oxidizing agent in particular for melting

agents, e.g. Potassium nitrate GR for analysis, ISO

(Cat. No. 1.05063).

Other known oxidizing agents are chromates

and dichromates, e.g.

Potassium chromate GR for analysis

(Cat. No. 1.04952) and Potassium dichromate GR for analysis,

ACS, ISO (Cat. No. 1.04864)

or finally, chlorates, e.g.

Potassium chlorate GR for analysis

(Cat. No. 1.04944).


3/10

What is the difference between ammonium carbamate

and ammonium carbonate?

Ammonium carbonate is the salt of carbonic

acid, ammonium carbamate is the salt of

carbamic acid. The latter is substantially more

stable than ammonium carbonate and only

converts to ammonium carbonate in an

aqueous solution, particularly when it is boiled.

What are monobasic and dibasic phosphates?

di-Sodium hydrogen phosphate (Na2HPO4)

e.g. Cat. No. 1.06580 is designated as a dibasic

phosphate and Sodium dihydrogen phosphate

(NaH2PO4) e.g. Cat. No. 1.06346 as a mono-basic phosphate.

What are primary, secondary and tertiary phosphates?

Primary phosphates are dihydrogen phosphates

(acid phosphates) with the general formulaM1+H2PO4 or M

2+(H2PO4)2.

Secondary phosphates are dihydrogen

phosphates with the general formula

M1+2HPO4 or M2+HPO4.

Tertiary phosphates are phosphates with the

general formula M13PO4 or M2+3(PO4)2.


4/10

What are bicarbonates?

Bicarbonates are synonymous with hydrogen

carbonates and include, for example, the

compounds

Potassium hydrogen carbonate GR for analysis

(Cat. No. 1.04854) and

Sodium hydrogen carbonate GR for analysis,

ACS (Cat. No. 1.06329).

What are salmiac and spirit of hartshorn?

Salmiac is the former name for ammonium

chloride and spirit of hartshorn the former

name for aqueous ammonia solution.

What does the residual content of

potassium sulfide 44 % consist of?

Potassium sulfide about 44 %, small lumps,

GR for analysis (Cat. No. 1.05134), is a mixture

of potassium polysulfide (K2SX where x = 3 to 7)and potassium thiosulfate. The rest can be

interpreted from the variable size of x.

Why do salts cake?

Substance-specific, thermal transition points,such as the liberation of water of crystallization

in the case of temperature fluctuations often

cause caking. This effect occurs in particular in

salts containing water of crystallization, as well

as in hygroscopic salts.


5/10

How should decahydrates and dodecahydrates be stored?

Decahydrates and dodecahydrates, such as

Sodium carbonate decahydrate GR

for analysis, ISO (Cat. No. 1.06391) or

di-Sodium hydrogen phosphate

dodecahydrate GR for analysis, ISO

(Cat. No. 1.06579)

liberate part of their water of crystallization

at about 33 C. They melt, so to speak, in theirown water of crystallization. This is why it is

important to store and transport these

compounds at a cool temperature (below 20 C),

particularly during the summer months.

How can iodine be dissolved in water?

Iodine only exhibits a very slight solubility in

water, but dissolves easily in a concentrated

potassium iodide solution by forming

complexes. The solution should, however,

only be further diluted when all the iodinehas dissolved, otherwise the remaining iodine

will only dissolve extremely slowly, despite the

presence of potassium iodide.


6/10

Which inorganic salts are common reducing agents?

Known reducing agents are compounds, in which

either the cation or the central atom of the

anion can easily change to a higher oxidation

state, for example:

Ammonium iron(II) sulfate hexahydrate GR

for analysis, ISO (Cat. No. 1.03792),

Iron(II) sulfate heptahydrate GR for analysis,

ACS, ISO (Cat. No. 1.03965), Tin(II) chloride dihydrate GR for analysis, ACS

(Cat. No. 1.07815)

and compounds containing sulfur, such as

Sodium disulfite (sodium metabisulfite)

GR for analysis, ACS (Cat. No. 1.06528),

Sodium dithionite LAB (Cat. No. 1.06507) or Sodium sulfite anhydrous GR for analysis, ACS

(Cat. No.: 1.06657).


7/10

Can inorganic salts also be used for pharmaceutical purposes?

Inorganic salts GR for analysis are tested for

relevant specifications and not pharmacopoeial

requirements.

We offer extra pure inorganic salts as active

substances and auxiliaries for the pharma-

ceutical industry that are analyzed with respect

to the above-mentioned pharmacopoeias.

The current editions of the pharmacopoeias areapplicable in each case.

What does ACS mean?

Items with the quality designation ACS are

tested according to the requirements of theACS American Chemical Society.

The ACS requirements include not only the strict

specifications for reagents, but also the analytical

guidelines.


8/10

What does ISO mean?

Items with the quality designation ISO

are tested according to the specifications

of the ISO International Organization for

Standardization.

Which salts can be used to produce constant humidity?

A range of inorganic salts that can be used tohelp produce various constant humidity levels

in a closed room is contained in Lab Tools

Tables for the Laboratory (Order No. W280111)

and in the brochure Purification Methods

and Reagents for Sample Preparation and

Product Purification (Order No. W283132).


9/10

What are stabilized products?

Some compounds fall under the German

Explosives Act (Sprengstoffgesetz) and may

not be marketed as dry substances, but only

mixed with water. These include, for example,

the compounds

Ammonium dichromate GR for analysis,

stabilized with 0.5 3 % water

(Cat. No. 1.01130), Ammonium nitrate, stabilized with min. 3 %

water GR for analysis (Cat. No. 1.01188).

How can inorganic salts be disposed of?

Our experienced employees will advise you ondisposal matters. If you wish to return chemicals

to Merck, please contact our Retrologistik

Service

Phone: +49-6151- 72 85 00,

Fax: +49-6151- 72 85 80,

E-mail: [email protected],Internet: www.retrologistik.de.

We will send you all the necessary documents,

such as the statement of acceptance, collection

order form, transport documents and terms of

acceptance.


10/10

If you have any

further questions,

dont hesitate

to get in touch with us.

We would be pleased

to be of assistance.

Merck KGaA

64271 Darmstadt, Germany

Fax: +49-6151- 72 60 80

www.merck.de

E-Mail: [email protected]

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