Compounds and solutions

Methane is a compound of carbon and hydrogen, with the formula CH4. The mass of a carbon atom is 12, and the mass of each hydrogen atom is 1, so its formula mass is 16. 

You can find what fraction of the total mass is carbon, and what fraction is hydrogen, like this  

Mass of hydrogen as fraction of total mass = -total m - 

These fractions are usually written as percentages. To change a fraction to a percentage, you just multiply it by 100  

So 75% of the mass of methane is carbon, and 25% is hydrogen. We say that the percentage composition of methane is 75% carbon, 25% hydrogen. 

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Solution hardening is not confined to 5000 series aluminium alloys. The other alloy series all have elements dissolved in solid solution and they are all solution strengthened to some degree. But most aluminium alloys owe their strength to fine precipitates of intermetallic compounds, and solution strengthening is not dominant... 

Transition metal ions. Transition metal ions impart color to many of their compounds and solutions, (a) Bottom row (left to right) iron(lll) chloride. copper ll) sulfate, manganese(ll) chloride, cobalt(ll) chloride. Top row (left to right) chromium(lll) nitrate, iron(ll) sulfate, nickel(ll) sulfate, potassium dichromate, (b) Solutions of the compounds in (a) in the order listed above. 

The UV spectra of nitronates, which are not functionalized at the a-C atom, have an intense absorption at 230 to 240 nm, which is very similar in characteristics to UV absorption of salts of nitro compounds and solutions of aci-nitro compounds in protic solvents. Since standard alkyl- or silyl nitronates cannot have ionic structures, the presence of the above mentioned absorption in the UV spectra of nitronates, unambiguously confirms, that these compounds have the structures of O-esters. 

Progress was made in the theoretical interpretation of the spectra of rare earth compounds and solutions in terms of energy level structure, in particular those of Pr3+ and Tm3+ with 4f2 and 4f12 configurations, respectively [123,124]. Differences in interpretation of the bands existed which were resolved in favour of f-f transitions [125]. Then the complex spectrum of Nd3+(4f3) was analyzed [126]. Jorgensen was one of the first to identify systematically the energy levels of lanthanide aquo ions [127]. 

The general chemistry of Ac3 in both solid compounds and solution, where known, is very similar to that of lanthanum, as would be expected from the similarity in position in the Periodic Table and in radii (Ac3, 1.10 La3, 1.06 A) together with the noble gas structure of the ion. Thus actinium is a true member of Group 3, the only difference from lanthanum being in the expected increased basicity. The increased basic character is shown by the stronger absorption of the hydrated ion on cation-exchange resins, the poorer extraction of the ion from concentrated nitric acid solutions by tributyl phosphate, and the hydrolysis of the trihalides with water vapor at 1000°C to the oxohalides AcOX the lanthanum halides are hydrolyzed to oxide by water vapor at 1000°C. 

Although water is a polar molecule, pure water does not carry an electric current. It is a good solvent for many ionic compounds, and solutions of ionic compounds in water do carry electric currents. The charged particles in solution move freely, carrying electric charges. Even a dilute solution of ions in water becomes a good conductor. Without ions in solution, there is very little electrical conductivity. 

Solute transport, adsorption, and precipitation reactions can make it difficult to reconstruct decomposition stoichiometries from pore-water profiles alone, particularly within the bioturbated zone. Because the general trends and limits on N/P and N/C stoichiometry are evident from the previous considerations no further modeling will be done here. An adequate explanation for the higher NH//HPO4 -concentration ratios in the deeper pore water at inshore relative to offshore stations (Fig. 14) requires decomposition experiments below 10 cm, together with direct examination of the solid phase for phosphate compounds and solute transport modeling. 

O—H, and N—H. These bands enable the quantitative characterization of polymers, chemicals, foods, and agricultural products for analytes such as water, fatty acids, proteins, and the like. In many cases, the use of NIR reflectance spectroscopy has been able to replace time consuming, classical wet chemical analyses, such as the Kjeldahl method for protein nitrogen and the Karl Fischer titration for water content. The NIR region has been used for qualitative studies of hydrogen bonding, complexation in organometallic compounds, and solute-solvent interactions because the NIR absorptions are sensitive to intermolecular forces. 

Spectroscopic Properties of the f-Elements in Compounds and Solutions, W.T. CamaU, J.V. Beitz, H. Crosswhite, K. Rajnak, and J.B. Mann. In Systematics and the Properties of the Lanthanides, S.P. Sinha (Ed.), D. Reidel Publishing Company, Boston, chapter 9,... 

Thus our definition of the second law has led to a function, G, which will always decrease to a minimum in spontaneous processes in systems having specified values of T and P. It is an extremely useful thermodynamic potential. All we have to do is to find a way to get measurable values of this function for all pure compounds and solutes, and to find how they change with T, P, and concentration, and we will then be able to predict the equilibrium configuration of any system by minimizing G. 

Silver ion titrations are nice because AgN03 is a primary standard. After drying at 110°C for 1 h to remove moisture, the solid has the exact composition AgN03. Methods for finding the end point in silver titrations are described in Section 6-6. Silver compounds and solutions should be stored in the dark to prevent photodecomposition and should never be exposed to direct sunlight. 

KEMS has a long history. It was first applied in 1948 [11] and was used quite extensively in the 1960s and 1970s to study the vapors above pure compounds. There are a number of excellent reviews on this technique [12-18]. More recently some groups have extended this technique to multiple-component solutions, as discussed in the review by Kato [3]. Today there are only a small number of groups worldwide that utilize KEMS for both pure compound and solution thermodynamics. 

The part of Berthollet s theory which gave Proust the most trouble was that denying any distinction between true compounds and solutions solutions are chemical compounds, produced by the same forces as those operating in any other type (e.g. oxides) but exerted more feebly. When a salt dissolves in water the salt and water are united by affinity when salt crystallises on cooling it is because cohesion in the solid outweighs the attraction of salt and water, and when it separates on evaporation it is because the elasticity of the vapour of the solvent predominates. Berthollet pressed for precise definitions of compounds combinaisons) and solutions dissolutions and at the same time reminded Proust that Vauquelin and Klaproth, both skilled analysts, had foimd results differing from those of Proust for substances which the latter regarded as true compounds. 

They can thus largely influence the efficiency of the catalytic ozonation processes. In regard to the last aspect, it should be noted that most of the studies are still performed using model compounds and solutions, and thus the application to real wastewater, where the cited inorganic ions and natural organic matter are often present, may result in completely different behavior. 

While spectra of actinide compounds and solutions exhibiting other than the 3 -f-valence state are well known, systematic analyses of the electronic structure in other valence states are very tentative at present. Extensive experimental analysis... 

When not available, liquid surface tensions (pure compounds and solutions) can be estimated using predictive methods like those based on parachors and group contributions, solubility parametes (including Hansoi solubility parameters) and corresponding states. Alternatively, they can be estimated from thermodynamic models like UNIFAC and SAFT combined with the gradient or the density functional theories. For a review of the latter, see Kontogeorgis and Folas (2010). Some of the most important direct methods for estimating surface tension arc briefly described here. 

When not available, liquid surface tensions (pure compounds and solutions) can be estimated using predictive methods like those based on parachors and group contributions, solubility parameters (including Hansen parameters) and corresponding states. 

Transition metai ions. Transition metal ions impart color to many of their compounds and solutions. 

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