Hazardous Chemicals Handbook (pdf) - CCC

Table 3.3 Important common physical properties
Gas
Density
Critical temperature, critical pressure (for liquefaction)
Solubility in water, selected solvents
Odour threshold
Colour
Diffusion coefficient
Liquid
Vapour pressure–temperature relationship
Density; specific gravity
Viscosity
Miscibility with water, selected solvents
Odour
Colour
Coefficient of thermal expansion
Interfacial tension
Solid
Melting point
Density
Odour
Solubility in water, selected solvents
Coefficient of thermal expansion
Hardness/flexibility
Particle size distribution/physical form, e.g. fine powder, flakes, granules, pellets, prills, lumps
Porosity
HX = H + + X –
Examples include hydrochloric acid, nitric acid, and sulphuric acid. These are strong acids which
are almost completely dissociated in water. Weak acids, such as hydrogen sulphide, are poorly
dissociated producing low concentrations of hydrogen ions. Acids tend to be corrosive with a
sharp, sour taste and turn litmus paper red; they give distinctive colour changes with other
indicators. Acids dissolve metals such as copper and liberate hydrogen gas. They also react with
carbonates to liberate carbon dioxide:
2HCl + Cu = CuCl 2 + H 2
2HCl + CaCO 3 = CaCl 2 + CO 2 + H 2O
Both acids and alkalis are electrolytes. The latter when fused or dissolved in water conduct an
electric current (see page 55). Acids are considered to embrace substances capable of accepting
an electron pair. Mineral acids have wide usage as indicated by Table 3.4.
Bases
Alkalis tend to be basic compounds which dissociate in water to produce hydroxyl ions, OH –
thus:
XOH = X + + OH –
BASES 27
Specifically, an alkali is a hydroxide of one of the alkali or alkaline earth metals. Examples
include the hydroxides of potassium, sodium, and calcium (where X is K, Na, and Ca, respectively).