Mercury, 47 freezing

Mercury freezes at -40°Cand is a liquid at room temperature. 

Mercury freezes at -38.87°C. What are the freezing points on the Fahrenheit and Kelvin scales ... 

For a number of years, thallium sulfate had been used in rodenticides. Some use of thallium has been made in connection with alloys for low-temperature applications, particularly for switches, seals, and thermometers. The ternary eutectic mercury-thallium-indium alloy has a freezing point of —63.3 JCt while the binary eutectic mercury-thallium alloy has a freezing point of — 60°C. These freezing points are considerably lower than that of mercury usually used for similar applications at higher temperatures. Mercury freezes at —38.87JC. 

At atmospheric pressure (i.e. 760 mm of mercury), freezing point of pure water is 0°C and boiling point of pure water is 100°C... 

In a report on the record low temperatures in Antarctica, Chemical and Engineering News said at one point that the mercury dropped to — 76°C. In what sense is that possible Mercury freezes at —39 C. 

Mercury freezes at — 38.9°C nitrogen boils at — 195.8°C. How can a boiling point be lower than a freezing point ... 

Liquid mercury freezes (becomes solid) at about — 40° Liquid carbonic acid boils at about. . . — 80°... 

Beckmann thermometer A very sensitive mercury thermometer with a small temperature range which can be changed by transferring mercury between the capillary and a bulb reservoir. Used for accurate temperature measurements in the determination of molecular weights by freezing point depression or boiling point elevation. 

If, on the other hand, the thermometer has previously been used at some temperature below the freezing-point of benzene, when the bulb is originally placed in the beaker of water at 7-8 C., the mercury will rise in the capillary and ultimately collect in the upper part of the reservoir at a. When the expansion is complete, again tap the thermometer sharply at R so that this excess of mercury drops down into b, and then as before check the success of the setting by placing the thermometer m some partly frozen benzene. In either case, if the adjustment is not complete, repeat the operations, making a further small adjustment, until a satisfactory result is obtained. 

When freshly exposed to air, thallium exhibits a metallic luster, but soon develops a bluish-gray tinge, resembling lead in appearance. A heavy oxide builds up on thallium if left in air, and in the presence of water the hydride is formed. The metal is very soft and malleable. It can be cut with a knife. Twenty five isotopic forms of thallium, with atomic masses ranging from 184 to 210 are recognized. Natural thallium is a mixture of two isotopes. A mercury-thallium alloy, which forms a eutectic at 8.5% thallium, is reported to freeze at -60C, some 20 degrees below the freezing point of mercury. 

Acetic acid, fp 16.635°C ((1), bp 117.87°C at 101.3 kPa (2), is a clear, colorless Hquid. Water is the chief impurity in acetic acid although other materials such as acetaldehyde, acetic anhydride, formic acid, biacetyl, methyl acetate, ethyl acetoacetate, iron, and mercury are also sometimes found. Water significantly lowers the freezing point of glacial acetic acid as do acetic anhydride and methyl acetate (3). The presence of acetaldehyde [75-07-0] or formic acid [64-18-6] is commonly revealed by permanganate tests biacetyl [431-03-8] and iron are indicated by color. Ethyl acetoacetate [141-97-9] may cause slight color in acetic acid and is often mistaken for formic acid because it reduces mercuric chloride to calomel. Traces of mercury provoke catastrophic corrosion of aluminum metal, often employed in shipping the acid. 

Chemical Designations - Synonyms. Calochlor Corrosive mercury chloride Corrosive sublimate Mercury bichloride Mercury (II) chloride Mercury perchloride Chemical Formula-. HgClj Observable Characteristics(as shipped)-. Solid Color. White colorless Odor. None. Physical and Chemical Properties - Physical State at 15 X and 1 atm. Solid Molecular Weight-. 271.50 Boiling Point at I atm. 576, 302, 575 Freezing Point 531, 277, 550 Critical Temperature Not pertinent Critical Pressure Not pertinent Specific Gravity 5.4 at 20 °C (solid) Vapor (Gas) Specific Gravity Not pertinent Ratio of Specific Heats of Vapor (Gas) Not pertinent Latent Heat of Vaporization Not pertinent Heat of Combustion Heat of Decomposition Not pertinent. 

From the ventilation point of view, the fixed points -38.83 °C (triple-point of mercury), 0.010 °C (triple-point of water), 29.76 °C (melting point of gallium), and 156.60 °C (freezing point of indium) are of relevance. The triple-point of water is relatively simple to achieve and maintain with a triple-point apparatus. Some freezing point cells are covered in standards. In practical temperature calibration of measuring instruments, the lTS-90 fixed points are not used directly. 

Self-Tfst 7.8A Calculate the standard entropy of fusion of mercury at its freezing point (see Table 6.3). 

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