Dioxide in the Air

Upper curve Atmospheric CO deduced from air trapped in Antarctic ice and from direct atmospheric measurements. Lovjer curve Atmospheric temperature at the level where precipitation forms is deduced from isotopic composition of ice. 

I erhaps the largest chemical experiment ever conducted is our injection of carbon dioxide into the atmosphere in sufficient quantity to alter the cycle of CO2 concentration that has persisted for at least 800 000 years. CO2 is produced by combustion of fossil fuels (coal, oil, natural gas), which are our predominant source of energy. 

CO2 acts as a greenhouse gas to affect Earth s surface temperature. Earth absorbs sunlight and then emits infrared radiation. The balance between sunlight absorbed and radiation sent back to space determines the surface temperature. A greenhouse gas absorbs infrared radiation and reradiates some of it back to the ground. By intercepting some of Earth s radiation, CO2 keeps our planet warmer than it would otherwise be. 

Carbon dioxide from air dissolves in water to make carbonic acid, which has two acidic protons. Later in this chapter, we explore potential effects of dissolving massive amounts of this acid in the ocean. Carbonic acid from CO2 and amino acids from proteins are examples of polyprotic acids—those having more than one acidic proton. 

Amino acids from which proteins are built have an acidic carboxylic acid group, a basic amino group, and a variable substituent designated R  

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Lead dioxide candle A device for determining the amount of sulfur dioxide in the air. The SO, reacts with a film of lead dioxide to produce lead sulfate, which is measured to determine the concentration. Leakage The rate of fluid loss from an enclosure due to a pressure difference between the inside and outside of the enclosure. 

Sulphur dioxide in the air originates from the combustion of fuel and influences rusting in a number of ways. For example, Russian workers consider that it acts as a cathodic depolariser , which is far more effective than dissolved oxygen in stimulating the corrosion rate. However, it is the series of anodic reactions culminating in the formation of ferrous sulphate that are generally considered to be of particular importance. Sulphur dioxide in the air is oxidised to sulphur trioxide, which reacts with moisture to form sulphuric acid, and this in turn reacts with the steel to form ferrous sulphate. Examination of rust Aims formed in industrial atmospheres have shown that 5% or more of the rust is present in the form of iron sulphates and FeS04 4H2 0 has been identified in shallow pits . 

Among other contributions of Arrhenius, the most important were probably in chemical kinetics (Chapter 11). In 1889 he derived the relation for the temperature dependence of reaction rate. In quite a different area in 1896 Arrhenius published an article, "On the Influence of Carbon Dioxide in the Air on the Temperature of the Ground." He presented the basic idea of the greenhouse effect, discussed in Chapter 17. 

X 10 4 M HCl(aq) with phenolphthalein indicator to see how much NaOH was left unreacted. They found that 30.2 mL of HCl(aq) was required to reach the stoichiometric point, (a) Write the balanced chemical equation for the reaction of S02 and water, (b) What amount of NaOH (in mol) had reacted with the SO, (c) What was the concentration of sulfur dioxide in the air, in parts per million ... 

Fig. 11-15 Variation in the vertical distribution of carbon dioxide in the air around a forest with time of day. (Reprinted with permission from B, Bolin (1970). The carbon cycle. In The Biosphere," p. 51, W. H. Freeman, NY.)...

Apparently the copper had somehow come from the power line. When other similar areas, under power lines were investigated, no substantial increase in the concentration of copper was evident. This situation was different from the others in that it was in an industrialized area. It is hypothesized that the erosion of the copper was much greater there because of the presence of sulfur dioxide in the air. This is known as a synergistic effect. By themselves neither the S02nor the copper line would have caused the death of the sheep. They both had to be present. 

Vinegar is recommended for cleaning a variety of appliances and other items that may be stained by hard water deposits. Automatic coffee makers, steam irons, dishwashers, teapots, faucet heads, and shower heads — over time, all accumulate calcium deposits from hard water. Groundwater, that is, water that travels through soil and rocks, accumulates dissolved calcium ions as a consequence of the natural weathering of minerals that contain calcium such as limestone and calcite, shells, and coral. At the same time, carbon dioxide in the air dissolves in water to form carbonate ions that combine with calcium ions to form a white solid, calcium... 

Whether for a class demonstration, a practical joke, or perhaps a clandestine activity, disappearing ink is a fascinating substance. What is the secret to its action One formulation of disappearing ink contains a common acid-base indicator, that is, a substance that by its color shows the acid or basic nature of a solution. One acid-base indicator that shifts from a colorless hue under acidic conditions to a deep blue color in alkaline solutions is thymolphthalein. If the indicator starts off in a basic solution, perhaps containing sodium hydroxide, the typical blue color of an ink is perceived. How does the ink color disappear This behavior is dependent upon the contact of the ink with air. Over time, carbon dioxide in the air combines with the sodium hydroxide in the ink solution to form a less basic substance, sodium carbonate. The carbon dioxide also combines with water in the ink to form carbonic acid. The indicator solution responds to the production of acid and returns to its colorless acid form. A white residue (sodium carbonate) remains as the ink dries. 

Water, in the form of rain, is needed for rusting to occur. Carbon dioxide in the air dissolves in water to form carbonic acid, H2C03(aq). 

No methods for determining chlorine dioxide in biological materials were located. Most studies concerning human health effects measure the concentrations of chlorine dioxide in the air or in water. The measurement of chlorine dioxide in biological materials is not commonly used because of the rapid conversion of chlorine dioxide to chlorine-containing metabolites, such as chlorite and chloride ions. 

Bases also have their domestic uses. The various kinds of soda found in the home - baking soda, washing soda and caustic soda - are all bases. But the widest used base of all is lime. Besides its agricultural use, lime is a vital ingredient in cement, mortar, plaster and concrete. The lime reacts with carbon dioxide in the air and hardens the mixture as it dries out. 

Farmers use lime (calcium hydroxide) to sweeten" an acid soil, and make heavy, clay-laden soils more workable. Carbon dioxide in the air dissolves in water to form the very weak carbonic acid (hydrogen carbonate). The alkaline lime neutralizes any traces of carbonic acid in the earth, producing calcium carbonate (or chalk) - and some more water. 

Transition-metal -phthalocyanines as catalysts in acid medium. To prevent carbonate formation by the carbon dioxide in the air or that produced by oxidation of carbonaceous fuels, an acid electrolyte is necessary hence it is important to find electrocatalysts for an acid medium. Independently of Jasinski, we were soon able to show 3>4> that under certain conditions the reduction of oxygen in dilute sulfuric acid proceeded better with phthalocyanines on suitable substrates than with platinum metal. The purified phthalocyanines were dissolved in concentrated sulfuric acid and precipitated on to the carbon substrate by addition of water. This coated powder was made into porous electrodes bound with polyethylene and having a geometrical surface of 5 cm2 (cf. Section 2.2.2.1.). The results obtained with compact electrodes of this type are shown in Fig. 6. 

Lead azide, like hydrazoic acid, is liable to undergo oxidation and reduction reactions. It is partially decomposed by atmospheric oxygen to form free hydrazoic acid, nitrogen and ammonia. This reaction is promoted by the presence of carbon dioxide in the air. When boiled in water, lead azide undergoes slow decomposition with the evolution of hydrazoic acid. 

Protection from Carbon Dioxide.—In working with substances in alkaline solutions, it is sometimes necessary to protect the solution from the carbon dioxide in the air. This is particularly true when compounds are present that can form insoluble carbonates. In all such cases, the operations involved must be carried out in closed vessels containing air that has been purified by drawing it over a suitable absorbent such as soda lime. When... 

In a number of ways, however, humans have surpassed volcanoes as sources of pollution. In the United States alone, for example, industrial and other human activities have been depositing about 20 million tons of sulfur dioxide in the air every year since around 1950 By one estimate, human activities account for about 70 percent of all sulfur that enters the global atmosphere. To... 

When water falls through the atmosphere as rain, ice, or snow, the water can combine with carbon dioxide in the air and produce carbonic acid. 

As the slaked lime dries, it reacts with carbon dioxide in the air to produce limestone, the raw material from which the final product was made. 

Increasing carbon dioxide concentration and decreasing stratospheric ozone concentration of the atmosphere may alter global radiation fluxes. Presumably a primary result of more carbon dioxide in the air will be warming. While incoming solar radiation is not absorbed... 

The aqueous calcium hydroxide in wet concrete is able to react with carbon dioxide in the air. 

Costonis et al. (33) were unable to demonstrate a positive correlation between ambient sulfur dioxide levels and inorganic sulfur ion accumulation in the needles of pines which are injured by relatively low levels of sulfur dioxide in the air. White pines growing in air polluted with more than 0.25 ppm of sulfur dioxide are often stunted, and a direct correlation can be obtained between plant growth and ambient S02 levels (34). However, tissue analysis does not reveal a measurable rise in sulfur level as inorganic sulfate ions. It is posible that the excess sulfur is incorporated into cell protein, but the data conflict (28, 35). For these reasons, it is not possible to follow sulfur accumulation in plants chronically exposed to low levels of ambient S02 without resorting to labeled S02. 

Carbon Dioxide in the Air.—It is to Dr. Black that we owe the first proof of the existence of carbon dioxide in the air, during the years 1752-1754.7 He termed it fixed air. Lavoisier, however, showed that it was a compound of oxygen and carbon. 

The actual proportion of carbon dioxide in the air varies very considerably according to circumstances. Whalley reported that in a Scottish mine the carbon dioxide in the air near the coal face reached T21 per cent., whilst on the pavement it was no less than 4-56 per cent. Levy,1 in discussing the abnormal air of New Granada, points out that owing to forest fires the percentage of carbon dioxide in the air would often rise to 0-49 per cent. These cases, however, are abnormal. 

Compounds of carbon and hydrogen, together with oxygen and nitrogen, make up almost 100 % of the compounds in the cells of our bodies. Without carbon we would not exist. Where does it all come from It is recycled to us via foods. Green plants obtain their carbon from the carbon dioxide in the air. 

Sulfur dioxide in the air dissolves in the rain, along with some of the oxygen present, forming a weak solution of sulfuric acid ... 

Metal Carbonates. In certain cases, metal carbonates are less soluble than their corresponding hydroxides. Natural formation of carbonates from carbon dioxide in the air, referred to as carbonation, depends on pC02 and pH. The carbonation process in the alkaline pH range is... 

Barium Hydroxide, 0.2 N [17.14 g Ba(OH)2 per 1000 mL] Dissolve about 36 g of barium hydroxide [Ba(0H)2-8H20] in 1 L of recently boiled and cooled water, and quickly filter the solution. Keep this solution in bottles with well-fitted rubber stoppers with a soda-lime tube attached to each bottle to protect the solution from carbon dioxide in the air. Standardize as follows Transfer quantitatively about 60 mL of 0.1 A hydrochloric acid, accurately measured, to a flask add 2 drops of Phenolphthalein TS and slowly titrate with the barium hydroxide solution, with constant stirring, until a permanent pink color is produced. Calculate the normality of the barium hydroxide solution and, if desired, adjust to exactly 0.2 A with freshly boiled and cooled water. 

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