Chemical thermometer

Tn addition to the error due to the exposed stem, ordinary chemical thermometers of low cost are subject to errors due to irregularities in the bore and sometimes the scale graduations may not be very accurate. " It is therefore essential to check the thermometer at several temperatures against the melting points of pure solids or the boiling points of pure liquids as described below. The application of an exposed stem correction will of course be unnecessary if the thermometer is calibrated in this way. A calibration curve may then be drawn upon graph " paper from the data thus obtained. Temperatures at intervals of about 20° are marked as abscissae and the corrections to be added or subtracted as ordinates the points thus obtained are then connected by a smooth curve. The thermometer correction at any temperature may be read directly from the curve. 

H. R. Linden High temperature pyrolysis of coal with high energy sources seems to follow readily predictable paths similar to hydrocarbon pyrolysis. The effects of pressure, gas atmosphere, reaction time, and the volatile matter" content of the coal bear the same relationship to yields of methane, ethane, ethylene, acetylene, and hydrogen as for simple hydrocarbons. Effective reaction temperature, although not directly measurable, could be estimated by means of a suitable chemical thermometer, such as the C-. H-. -C. H4-H. system which approaches equilibrium very rapidly. As Dr. Given also noted, equating the volatile matter" to the reactive portion of the coal is an oversimplification but adequate for empirical purposes the C H ratio of the coal would probably be more suitable. 

Method of Obtaining Heat—Bottles—A Chemical Balance—Test Tube Racks—A Ring Stand—A Hydrogen Sulphide Generator — Necessary Apparatus — Test Tubes — Evaporating Dishes—Fire Clay Crucibles—Filter Paper—Graduated Cylinder—Chemical Thermometers—Pipette—Red and Blue Litmus Paper—Beakers—Pinch Cocks—Thistle Tubes—Flasks— Clamps—Chemicals for the Laboratory. Pages 40-62... 

The chemical thermometer used in the small laboratory should be graduated in Centigrade degrees as the Centigrade system is considered more scientific than the Fahrenheit system, and therefore it finds more universal use in the world of science. A word of... 

In order to use these relationships as a chemical thermometer, a normalization must be established to obtain p2. In principle, the temperature can be obtained from the equilibrium distribution of the olefins - if the system is in equilibrium at all. 

It is also recognized that errors in measuring the temperature, a major source of uncertainty in the determination of dynamic parameters, are often large in dynamic investigations involving rare isotopes. Indeed, chemical thermometers, such as methanol or glycerol are... 

These kinds of stores carry hobby/craft supplies, gimmicky science fair projects, ant farms and a low assortment of basic scienceware products such as beakers, thermometers, scales, rubber stoppers and most of the basic chemicals such as acids, bases and solvents. These places are listed in the chemicals section of any big city s yellow pages and are relatively safe places to get most of the basic lab necessities. The drawback is that they are really expensive and don t sell very large quantities of any chemical. It is possible to have these places special order a needed chemical as long as it s not a controlled chemical. 

The apparatus to use is seen in figure 13 which consists of a burette, thermometer, Erlenmeyer flask and a two-holed rubber stopper that has a small V-shaped wedge cut out of one side of the rubber stopper to allow the inside contents to vent. 31.5g of orangy-red fuming nitric acid (see chemicals section) is poured into the Erlenmeyer flask and the rubber stopper with its burette and thermometer is placed on to the... 

Mercury is used in the manufacture of thermometers, barometers and switchgear, and in the production of amalgams with copper, tin, silver and gold, and of solders. A major use in the chemical industry is in the production of a host of mercury compounds and in mercury cells for the generation of chlorine. Mercury has a significant vapour pressure at ambient temperature and is a cumulative poison. 

All reagents were purchased from Aldrich Chemical Company (except for trimethylacetyl chloride, which the checkers obtained from Acros) and were used without further purification. The checkers used a low temperature alcohol thermometer in place of a Teflon-coated themocouple. The third neck of the flask was left open to the atmosphere. 

A calorimeter Is a device used to measure heat flows that accompany chemical processes. The basic features of a calorimeter include an Insulated container and a thermometer that monitors the temperature of the calorimeter. A block diagram of a calorimeter appears in Figure 6-15. In a calorimetry experiment, a chemical reaction takes place within the calorimeter, resulting in a heat flow between the chemicals and the calorimeter. The temperature of the calorimeter rises or falls in response to this heat flow. 

How do we know the composition of the sun and other stars How can we measure the temperature inside a flame so hot that any thermometer would melt How can we explore chemical reactions among molecules that are much too tiny to see directly Light allows us to do all these things. The study of matter with electromagnetic radiation is called spectroscopy. 

For each of the following, note if a precipitate or a gas forms. The formation of water will not be obvious. When water forms, energy is usually given off. Therefore, if no product is immediately visible, insert a thermometer into the contents of the test tube to determine if heat is released. Use the increase in temperature as evidence for formation of water. If no evidence of a chemical reaction is evident, record No Reaction in the Evidence of Reaction column of Data Table 1. 

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