Mercury, liquid freezing/boiling point

Mercury is the only metal that is in a liquid state at room temperatures and remains liquid at temperatures well below the freezing temperature of water. Mercury is a noncombustible, heavy, silvery-colored metal that evenly expands and contracts with temperature and does not wet or stick to glass, which makes it ideal as a liquid for thermometers. Mercury is slightly volatile and will give off toxic fumes, especially if heated. Its has a unique melting point of —38.83°C, a boiling point of 3,56.73°C, and a density of 13.5336 g/cm. ... 

Routine measurements of temperature are done with a thermometer. Thermometers found in chemistry laboratories may use either mercury or a colored fluid as the liquid, and degrees Celsius (°C) as the units of measurement. The fixed reference points on this scale are the freezing point of water, 0°C, and the boiling point of water, 100°C. Between these two reference points, the scale is divided into 100 units, with each unit equal to 1°C. Temperature can be estimated to 0.1°C. Other thermometers use either the Fahrenheit (°F) or the Kelvin (K) temperature scale and use the same reference points, that is, the freezing and boiling points of water. Conversion between the scales can be accomplished using the formulas below. 

The nature of the phase rule can be induced from some simple examples. Consider the system represented in Figure 24-3. It is made of water-substance (water in its various forms), in a cylinder with movable piston (to permit the pressure to be changed), placed in a thermostat with changeable temperature. If only one phase is present both the pressure and the temperature can be arbitrarily varied over wide ranges the variance is 2. For example, liquid water can be held at any temperature from its freezing point to its boiling point under any applied pressure. But if two phases are present the pressure is automatically determined by the temperature, and hence the variance is reduced to 1. For example, pure water vapor in equilibrium with water at a given temperature has a definite pressure, the vapor pressure of water at that temperature. And if three phases are present in equilibrium, ice, water, and water vapor, both the temperature and the pressure are exactly fixed the variance is then 0. This condition is called the triple point of ice, water, and water vapor. It occurs at temperature +0.0099 C and pressure 4.58 mm of mercury. 

Bromosilane is a spontaneously flammable liquid with a freezing point of —94° and a boiling point of 1.9°. It is best stored in a stainless-steel cylinder with a stainless-steel needle valve, but alternatively, it may be stored as a liquid at —78° in a glass vessel. Bromosilane, unlike the iodo analog, does not attack mercury or stopcock grease. 

On the Reamur scale, which is no longer used, water freezes at 0°R and boils at 80°R. (a) Derive an equation that relates this to the Celsius scale, (b) Derive an equation that relates this to the Fahrenheit scale, (c) Mercury is a liquid metal at room temperature. It boils at 356.6°C (673.9°F). What is the boiling point of mercury on the Reamur scale ... 

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