Sodium acetate

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  Sodium acetate   
Names: sodium acetate
sodium ethanoate

Formula: NaCH3COO (anhydrous)
NaCH3COO · 3H2O (trihydrate)
SMILES: CC(=O)[O-].[Na+]
Molar mass: 82.034 g/mol (anhydrous)
136.078 g/mol (trihydrate)
Density: 1.528 g/cm3 (anhydrous)
1.45 g/cm3 (trihydrate)
Crystal system: monoclinic (trihydrate)
a=12.475 Å
12.4750 Å
1.2475 nm
, b=10.407 Å
10.4070 Å
1.0407 nm
, c=10.449 Å
10.4490 Å
1.0449 nm
α=90°
90°  
, β=112.65°
112°39′  
, γ=90°
90°  

Shapes:
https://media.crystalls.info/w/uploads/media/Oblique_rhombic_prism.json
https://media.crystalls.info/w/uploads/media/Trapezoidal_flat_prism.json
https://media.crystalls.info/w/uploads/media/Needle.json

Color: colorless
Melting point: 58 °C
331.15 K
136.4 °F
596.07 °R
(trihydrate)
328.2 °C
601.35 K
622.76 °F
1,082.43 °R
(anhydrous)
Refractive index: 1.455 (trihydrate)
Magnetic properties: diamagnetic
χ=-3.76 · 10-5cm³/mol
Stability: erodes during 15 minutes (trihydrate)
Hardness: fragile
Toxicity: non-toxic
LD50=3530mg/kg

Description

Organic compound, salt of alkaline metal sodium and organic acetic acid. From water solutions crystallizes as trihydrate.

Where to buy

In pharmacy (as "heating pad").

Precursors

Reaction between baking soda, sodium carbonate or hydroxide and acetic acid

Chemical equation:

CH3COOH + NaHCO3 = NaCH3COO + H2O + CO2
2CH3COOH + Na2CO3 = 2NaCH3COO + H2O + CO2
CH3COOH + NaOH = NaCH3COO + H2O

For preparation of 100.00g of sodium acetate trihydrate а 61.73g of soda or 38.94g of sodium carbonate or 29.39g of hydroxide and 63.04g of 70% acetic acid is required.
Add acid to the flask, then add small parts of sodium compound with stirring until heating will stop (attention, the solution may boil!) or, if you use carbonate, until carbon dioxide emission will stop. After reaction will stop, filter the solution and use it for crystal growing.

Reaction between sodium sulfate and calcium or lead(II) acetate

You can use sodium chloride instead of sulfate if you use lead salt.
Chemical equation:

Ca(CH3COO)2 + Na2SO4 = 2NaCH3COO + CaSO4
Pb(CH3COO)2 + Na2SO4 = 2NaCH3COO + PbSO4
Pb(CH3COO)2 + 2NaCl = 2NaCH3COO + PbCl2

For preparation of 100.00g of sodium acetate trihydrate а 118.38g of sodium sulfate decahydrate or 42.95g of sodium chloride and 64.73g of calcium acetate monohydrate or 139.38g of lead(II) acetate trihydrate is required.
Add to the flask with calcium or lead acetate solution small parts of sodium salt solution and stir. The large amount of poorly soluble precipitate will form. Settle it out and discard, then filter the solution carefully.

Influence of temperature

Compound is able to form a supersaturated solution or melt which doesn`t crystallize spontaneously itself and can remain in this state for long time. But an external action like touch or dust triggers a nuclear crystallization with releasing large amount of heat. This process used in heating pads and experiment called "Hot ice".
Cooling speed has much impact on end crystal form. For example, if cooling was too fast, the threads are formed, if cooling was slow, the needles are formed, and when temperature is constantly room temperature, the prismatic crystals are formed.

Storage conditions

For crystal storing use hermetic vessel with small amount of saturated solution at the bottom or place wadding moistened with such solution. You can use such alternatives as vessel with vaseline or vegetable oil, organic non-hygroscopic solvent (kerosene, benzine or paraffin). Also you can use acrylate polymer or another kinds of solidifying plastic.

Solubility

Temperatureгр/100,00 гр waterгр/100,00 гр ethanolгр/100,00 гр methanolгр/100,00 гр acetoneгр/100,00 гр ethylene glycolгр/100,00 гр formic acidгр/100,00 гр acetic acidгр/100,00 гр hydrazineгр/100,00 гр dimethylformamide
(anhydrous)(trihydrate)(anhydrous)(trihydrate)(anhydrous)(trihydrate)(trihydrate)(trihydrate)(trihydrate)(trihydrate)(trihydrate)
0°C
273.15 K
32 °F
491.67 °R
119
119 g/100g
54.338 %
79
79 g/100g
44.134 %
7.76
7.76 g/100g
7.201 %
10°C
283.15 K
50 °F
509.67 °R
121
121 g/100g
54.751 %
~124
124 g/100g
55.357 %
2.08
2.08 g/100g
2.038 %
15°C
288.15 K
59 °F
518.67 °R
~122
122 g/100g
54.955 %
~147
147 g/100g
59.514 %
~2.21
2.21 g/100g
2.162 %
16
16 g/100g
13.793 %
0.05
0.05 g/100g
0.05 %
20°C
293.15 K
68 °F
527.67 °R
~123
123 g/100g
55.157 %
~169
169 g/100g
62.825 %
2.33
2.33 g/100g
2.277 %
6
6 g/100g
5.66 %
25°C
298.15 K
77 °F
536.67 °R
~125
125 g/100g
55.556 %
~192
192 g/100g
65.753 %
5.3
5.3 g/100g
5.033 %
7.8
7.8 g/100g
7.236 %
29.03
29.03 g/100g
22.499 %
10.46
10.46 g/100g
9.469 %
1.5
1.5 g/100g
1.478 %
30°C
303.15 K
86 °F
545.67 °R
126
126 g/100g
55.752 %
~214
214 g/100g
68.153 %
40°C
313.15 K
104 °F
563.67 °R
~130
130 g/100g
56.522 %
~259
259 g/100g
72.145 %
50°C
323.15 K
122 °F
581.67 °R
134
134 g/100g
57.265 %
304
304 g/100g
75.248 %
60°C
333.15 K
140 °F
599.67 °R
~140
140 g/100g
58.333 %
70°C
343.15 K
158 °F
617.67 °R
146
146 g/100g
59.35 %
16.55
16.55 g/100g
14.2 %
80°C
353.15 K
176 °F
635.67 °R
153
153 g/100g
60.474 %
90°C
363.15 K
194 °F
653.67 °R
161
161 g/100g
61.686 %
100°C
373.15 K
212 °F
671.67 °R
170
170 g/100g
62.963 %
67.79
67.79 g/100g
40.402 %
Slightly soluble in diethyl ether.

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