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ipn [44]
3 years ago
9

When collecting your solid, why should the filter paper in the Buchner funnel be wetted with some of the cold recrystallization

solvent before a recrystallization mixture is filtered?
Chemistry
1 answer:
Mnenie [13.5K]3 years ago
6 0

Answer:   It is important to wet the filter paper in the Buchner funnel first with cold re crystallization solvent before the re crystallization mixture being filtered to minimize gaps around the edges of the filter paper which can prevent mechanical impurities from passing through. This gives better filtration where most impurities can be filtered. Furthermore, it provides good vacuum.

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Sodium acetate can be formed from the metathesis/double replacement reaction of sodium
telo118 [61]

Answer:

Explanation:

Sodium Acetate Trihydrate BP Specifications

Sodium Acetate BP

C2H3NaO2,3H2O

Action and use

Used in solutions for dialysis; excipient.

DEFINITION

Sodium ethanoate trihydrate.

Content

99.0 per cent to 101.0 per cent (dried substance).

CHARACTERS

Appearance

Colourless crystals.

Solubility

Very soluble in water, soluble in ethanol (96 per cent).

IDENTIFICATION

A. 1 ml of solution S (see Tests) gives reaction (b) of acetates.

B. 1 ml of solution S gives reaction (a) of sodium.

C. Loss on drying (As shown in the Relevant Test).

TESTS

Solution S

Dissolve 10.0 g in carbon dioxide-free water prepared from distilled water R and dilute to 100 ml 100 ml with the same solvent.

Appearance of solution

Solution S is clear and colourless.

pH

7.5 to 9.0.

Dilute 5 ml of solution S to 10 ml with carbon dioxide-free water.

Reducing substances

Dissolve 5.0 g in 50 ml of water, then add 5 ml of dilute sulphuric acid and 0.5 ml of 0.002 M potassium permanganate. The pink colour persists for at least 1 h. Prepare a blank in the same manner but without the substance to be examined.

Chlorides

Maximum 200 ppm.

Sulphates

Maximum 200 ppm.

Aluminium

Maximum 0.2 ppm, if intended for use in the manufacture of dialysis solutions.

Arsenic

Maximum 2 ppm, determined on 0.5 g.

Calcium and magnesium

Maximum 50 ppm, calculated as Ca.

Heavy metals

Maximum 10 ppm.

Iron

Maximum 10 ppm, determined on 10 ml of solution S.

Loss on drying

39.0 per cent to 40.5 per cent, determined on 1.000 g by drying in an oven at 130C.

Sodium Acetate FCC Food Grade, US Food Chemical Codex

C2H3NaO2 Formula wt, anhydrous 82.03

C2H3NaO2·3H2O Formula wt, trihydrate 136.08

DESCRIPTION

Sodium Acetate occurs as colorless, transparent crystals or as a granular, crystalline or white powder. The anhydrous form is hygroscopic; the trihydrate effloresces in warm, dry air. One gram of the anhydrous form dissolves in about 2 mL of water; 1 g of the trihydrate dissolves in about 0.8 mL of water and in about 19 mL of alcohol.

Function: Buffer.

REQUIREMENTS

Identification: A 1:20 aqueous solution gives positive tests for Sodium and for Acetate.

Assay: Not less than 99.0% and not more than 101.0% of C2H3NaO2 after drying.

Alkalinity Anhydrous: Not more than 0.2%; Trihydrate: Not more than 0.05%.

Lead: Not more than 2 mg/kg.

Loss on Drying: Anhydrous: Not more than 1.0%; Trihydrate: Between 36.0% and 41.0%.

Potassium Compounds: Passes test.

5 0
3 years ago
I know there are 4.5*10^-9 seconds in 4.5 nanoseconds, but when I enter it into my TI-30xIIs, I get 4.5*10^-10. I enter it as 4.
o-na [289]

Answer:

You are not using properly the function exponential in your calculator

Explanation:

When a number is too big or too small we use scientific notation. This is a number between 1 a 10 multiplied by a power of 10.

When you are writing 4.5*10^-9 you are actually writing 0.0000000045 in scientific notation.

When you enter this in the calculator you have to use the function EXP after the first two numbers.

Steps:    1) Enter 4.5

             2) Enter EXP

             3) Enter minus (-)

             4) Enter 9

8 0
4 years ago
Given the balanced equation:
Svet_ta [14]
Is there any answer choices before i get started on working out the problem
8 0
2 years ago
Compare/Contrast Make a song, poem, journal, story, etc comparing and contrasting metals, nonmetals, and metalloids. Be sure to
likoan [24]

Answer:

here you go

Explanation:

5 0
3 years ago
Is it possible for an electron in a hydrogen atom to emit a gamma ray by falling to a lower energylevel?
jeka94
No, its not possible. Let's go back to 4th grades' basic science.
"Energy can not be created or destroyed."
This applies to everything, even atoms!

Have a great day! ❤
7 0
3 years ago
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