Mercury in thermometers

The mercury in thermometers freezes at —38.9°C. What is this temperature in degrees Fahrenheit ... 

Any national deviation from EC legislation under national law must be notified to the European Commission, which may decide against the legislation. In these cases, the European Court of Justice may make the final decision on application of legal principles. Several Member States have taken regulatory measures beyond any enacted at the EU level. Cases include (i) Austria s ban on polybrominated biphenyls (PBB) (ii) the Netherlands ban on mercury in thermometers and Denmark s near-total ban on all uses of lead. In some instances, the European Commission has challenged the action of a Member State [251]. The most famous case was when Sweden banned trichloroethylene (TCE). The European Court of Justice held that Sweden was entitled to the ban because proportionality was respected through a system of authorisations [252],... 

Chemical kits describe any container housing small quantities of different chemicals used for medical, analytical, or testing purposes. The individual chemicals may exhibit one or more hazards, although they must be compatible with the other contents. First aid kits are convenient packages or boxes of medical supplies to provide immediate and sometimes makeshift medical attention. They may include multiple different materials, some of which will be hazardous (e.g., drugs, alcohols, mercury in thermometers) ... 

Corrected Melting-points. In all the above determinations of melting-points, the values obtained are described as uncorrected, since no allowance has been made for the fact that the column of mercury in the thermometer is at a lower temperature than that in the bulb. For most purposes it is sufficient to record this uncorrected value, which is usually only slightly lower than the corrected value. 

For this purpose the thermometer has a reserve supply of mercury in the reservoir R. For working at low temperatures, more mercury is required in the bulb, and an extra supply is brought down from R for working at higher temperatures, less mercury is required in the bulb to enable readings to be made on the scale S, and therefore a suitable quantity of mercury is detached from that in the bulb and deposited in the reservoir. 

Industrial and Control Instruments. Mercury is used in many industrial and medical instmments to measure or control reactions and equipment functions, including thermometers, manometers (flow meters), barometers and other pressure-sensing devices, gauges, valves, seals, and navigational devices (see Pressure measurements Process control Temperature measurement). Whereas mercury fever thermometers are being replaced by... 

The use of mercury for extracting precious metals by amalgamation has a long history and was extensively used by Spain in the sixteenth century when her fleet carried mercury from Almaden to Mexico and returned with silver. However, environmental concerns have resulted in falling demand and excess production capacity. It is still used in the extraction of gold and in the Castner-Kellner process for manufacturing chlorine and NaOH (p. 72), and a further major use is in the manufacture of batteries. It is also used in street lamps and AC rectifiers, while its small-scale use in thermometers, barometers and gauges of different kinds, are familiar in many laboratories. 

A 500-ml three-necked flask is fitted with a thermometer, a condenser, and a gas dispersion tube. A tube from the condenser outlet dips below the surface of mercury in a side-arm test tube. The mercury is covered with a layer of acetone, which serves to destroy excess diborane by the reaction to form diisopropoxyborane, [(CH3)2CH0-LBH (Fig. 4.1). 

The temperature of air as indicated by a dry sensing element such as a mercury-in-glass thermometer. 

Temperature is measured indirectly, by observing its effect on the properties of a substance. A mercury-in-glass thermometer takes advantage of the fact that mercury, like other substances, expands as temperature increases. When the temperature rises, the mercury in the thermometer expands up a narrow tube. The total volume of the tube is only about 2% of that of the bulb at the base. In this way, a rather small change in volume is made readily visible. 

Mercury (II) oxide, 3-4 Mercury-in-glass thermometers, 7-8 Mercury thermometers, 2 Metabolic energy, 218 Metal A substance having characteristic... 

The volatile metal is separated by distillation and condensed. Mercury is the only metallic element that is liquid at room temperature (gallium and cesium are liquids on warm days). It has a long liquid range, from its melting point of — 39°C to its boiling point of 357°C, and so it is well suited for its use in thermometers, silent electrical switches, and high-vacuum pumps. 

Romans mined the mineral cinnabar (HgS) from deposits in Spain 2000 years ago, and in the sixteenth century the Spanish shipped mercury obtained from the same ore deposits to the Americas for the extraction of silver. Mercury is an important component of street lamps and fluorescent lights. It is used in thermometers and barometers and in gas-pressure regulators, electrical switches, and electrodes. 

The presence of trace quantities of mercury in a process stream can cause the catastrophic failure of brass heat-exchanger tubes, from the formation of a mercury-copper amalgam. Incidents have occurred where the contamination has come from unsuspected sources, such as the failure of mercury-in-steel thermometers. 

Storage chambers should be validated with respect to their ability to maintain the desired conditions, and, if so equipped, the ability to sound an alarm if a mechanical or electrical failure causes the temperature to deviate from preestabilished limits. They should also be equipped with recording devices, which will provide a continuous and permanent history of their operation. Logbooks should be maintained and frequent readings or mercury-in-glass, National Institute of Science and Technology traceable thermometers recorded. 

Most substances expand when heated and contract when cooled, but liquid mercury shows an especially large variation of volume with temperature. That is why it is so often used in thermometers and barometers. Mercury also mixes with a number of metals to form alloys called amalgams. Amalgam is a special name given to alloys of mercury. With silver it forms a silver amalgam, which quickly hardens. This is the silver filling used by dentists. 

Modern temperature scale proposed by G. Fahrenheit, defined by a thermometer, a law and three fixed points. Fahrenheit s thermometer was a mercury-in-glass one. Thermal expansion versus temperature was assumed linear. Three fixed points were defined 0°F temperature of a mixture of water, ice and ammonium chloride 32°F temperature of melting ice 96°F temperature of human body... 

Measuring body temperature is important for the detection of disease and assessment of the response to treatments. The first thermometer was developed by Galileo in 1603. Thermometers for measuring body temperature have been in use since about 1870. The first measurements taken were axillary, and later oral and rectal measuring methods were introduced. The working principle of those thermometers, the expansion of matter by temperature increase, is still used for body temperature measurement in mercury-in-glass thermometers. Electronic thermo-... 

The infrared ear thermometer is a major step in the development of thermometers for body temperature measurements. Compared to traditional mercury-in-glass or electronic contact thermometers it is more convenient, safer and faster. During its 10 years in the consumer market it has been gradually replacing conventional thermometers, especially for temperature measuring in children. 

For a more dense liquid, such as mercury, the relationship between l and T is linear - at least over a relatively narrow range of temperatures - so a viable mercury-in-glass thermometer may be constructed. But, because the temperature response is only linear over a narrow range of temperatures, we need to exercise... 

Uses Determining refractive index of minerals paint diluent dyed hexane is used in thermometers instead of mercury polymerization reaction medium calibrations solvent for vegetable oils alcohol denaturant chief constituent of petroleum ether, rubber solvent, and gasoline in organic synthesis. 

Another common use is as a liquid contact in electrical silent switches. Also, mercury-vapor produces the bluish-white light of streedights. However, mercury-vapor hghts now are being replaced by sodium-vapor lights that produce a yellowish-white hght. Mercury is used in thermometers and barometers, to coat mirrors, and in the electronics industry and several other industries. 

Thallium-mercury is an amalgam—not really a compound, but more hke an alloy mixture. It is used in low-temperature thermometers and as a substitute for mercury in low-temperature switches. 

Gallium, like mercury, is liquid at room temperature, but unlike mercury is much less hazardous. Its most interesting use is as a visualization tool of soft tissues and bone lesions in radiography. Industrial applications include use in high temperature thermometers, metal alloys, and as a substitute for mercury in arc lamps. 

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