Gaseous Compounds

Impurities can be removed by formation of a gaseous compound, as in the fire-refining of copper (qv). Sulfur is removed from the molten metal by oxidation with air and evolution of sulfur dioxide. Oxygen is then removed by reduction with C, CO, in the form of natural gas, reformed... 

The most common heterogeneous catalytic reaction is hydrogenation. Most laboratory hydrogenations are done on liquid or solid substrates and usually in solution with a slurried catalyst. Therefore the most common batch reactor is a stirred vessel, usually a stirred autoclave (see Figure 2.1.1 for a typical example). In this system a gaseous compound, like hydrogen, must react at elevated pressure to accelerate the process. 

For many calculations it is required to know the ratio of Cp/C, for a gaseous compound. The well-known expression Cp-C = R (where R is the universal gas constant) holds good only for gases under ideal conditions. When working with situations involving real gases, the relationship between Cp and C, is given as ... 

Thermal conductivities for gaseous compounds are important in unit operations involving heat transfer coefficients. Thermal conductivities can be readily computed from an empirical polynomial expression that has the following form ... 

Critical properties of gaseous compounds are useful in determining the P-V-T (Pressure-Volume-Temperalure) properties at nonideal conditions. The compressibility faetor Z is defined by the following relationship ... 

This chapter describes the fundamentals of gas cleaning technology in branches of removal of particulates and gaseous compounds. This chapter also includes the fundamentals of particulate and gaseous measurements technology. 

Inhaled gaseous compounds are absorbed in all parts of the respiratory system whereas particle size determines how deep into the airways the parti cles will he transported in the airstrearn. Shortness of breath is a typical sign of a chemical exposure that has affected the lungs, and it may be evoked through iminunological mechanisms (e.g., formaldehyde, ethyleneoxide), or through toxic irritation (formaldehyde, isocyanates, sulfur dioxide, nitrogen dioxide, Frequently the mechanism depends on the concentration ol the com... 

Microwave spectroscopy shows that the gaseous compound is predominantly in the rram-planar (Cj) configuration with the dimensions shown. The differences between the two N-O distances is notable. Despite the formal single-bond character of the central bond the barrier to rotation is 45.2kJmol- . Infrared data suggest that the trans-form is 2.3kJmoI more stable (AG°) than the cis- form at room temperature. 

Figure 19.28 The eclipsed (De ) structure of [Cr( ) -C6Hg)2] as revealed by X-ray diffraction, showing the two parallel rings 323 pm apart. Neutron diffraction shows the H atoms are tilted slightly towards the Cr, and electron diffraction on the gaseous compound shows that the eclipsed configuration is retained without rotation.

A similar situation exists for hydrochloric acid, HQ. This gaseous compound dissolves readily in water at 25°C ... 

A gaseous compound used to make both bubble gum and automobile tires was analyzed to determine its properties and toxicity. 

Chemical thermodynamics is concerned with the interrelation of various forms of energy and the transfer of energy from one chemical system to another in accordance with the first and second laws of thermodynamics. In the case of CVD, this transfer occurs when the gaseous compounds, introduced in the deposition chamber, react to form the solid deposit and by-products gases. 

Unlike bonding, direct boride deposition does not require a reaction with the substrate to form the boride. Both boron and metal atoms are supplied as gaseous compounds. 

There is a large variety of atmospheric sulfur compounds, in the gas, solid, and liquid phases. Table 7-3 lists a number of gaseous compounds, range of concentration, source, and sink (where known). As this list illustrates, a significant number of these gases contribute to the existence of oxidized sulfur in the forms of SO2 and sulfate aerosol particles. Table 7-4 lists the oxy-acids of sulfur and their ionized forms that could exist in the atmosphere. Of these the sulfates certainly are dominant, with H2SO4 and its products of neutralization with NH3 as the most frequently reported forms. 

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