| Salt is the simple compound sodium chloride (NaCl). Each molecule of salt consists of one atom of sodium (Na) combined with one atom of chlorine(Cl).
The molecular weight of NaCl is 58.5 (Na = 23 plus Cl = 35.5), therefore salt is made up of 39.3% Na and 60.7% Cl).
Salt crystallises in the cubic form. When salt is crystallised from aqueous solution it produces perfect cubic crystals, when in sufficient amount the crystals aggregate forming partially developed cubes.
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Arrangement Of Na & Cl Ions In A Sodium Chloride Lattice
Drawn by Roger Rickard (1996) |
Sodium chloride is chemically very stable and can be kept indefinitely, withstanding temperatures up to melting point (801oC) and beyond without decomposing. Salt will boil at 1413oC at normal atmospheric pressure.
Salt will absorb moisture in humidities above 75.3% at 20oC.
Solid sodium chloride has a density of 2.163g/cc at 20oC, however the bulk density of normal salt products are approximately 1.1kg/m3 for coarse grades and 1.2kg/m3 for fine.
Salt in water
Salt is readily soluble in cold water (35.7g in 100ml water at 0oC) and only slightly more soluble in hot water (39.12g in 100ml water at 100oC).
Saturated brine at 20oC contains 26.4% NaCl. Saturated brine will boil at 108.7oC (containing 28.7% salt by weight) and will solidify at -21.12oC (containing 23.3% salt by weight).
| Specific Gravity Of Solution @ 20oC % |
NaCl By Weight |
Dry Salt (grams) In 100 ml Water |
Quantities To Make One Litre |
| NaCl (grams) |
Water (ml) |
| 1.005 |
1 |
1.0 |
10.05 |
995 |
| 1.012 |
2 |
2.0 |
20.2 |
992 |
| 1.026 |
4 |
4.2 |
41.0 |
985 |
| 1.041 |
6 |
6.4 |
62.5 |
979 |
| 1.055 |
8 |
8.7 |
84.3 |
971 |
| 1.070 |
10 |
11.1 |
107.0 |
963 |
| 1.085 |
12 |
13.6 |
130.1 |
955 |
| 1.100 |
14 |
16.3 |
154.0 |
946 |
| 1.116 |
16 |
19.1 |
178.5 |
938 |
| 1.132 |
18 |
22.0 |
204.0 |
928 |
| 1.147 |
20 |
25.0 |
229.5 |
918 |
| 1.164 |
22 |
28.2 |
256.0 |
908 |
| 1.180 |
24 |
31.6 |
283.5 |
896 |
| 1.197 |
26 |
35.3 |
312.0 |
885 |
| 1.200 |
26.4 |
36.0 |
318.0 |
881 |
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