Carbon dioxide in the air

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. 

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.)...

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). 

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... 

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. 

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. 

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. 

Carbon dioxide in the air is the source of the carbon in plants. The plants synthesise, from the carbon dioxide and water, sugars for their own food and energy. They do this in the presence of sunlight in a process called photosynthesis. Some of the sugars join in long chains to form starch, as in cereals and potatoes, or cellulose as in cotton and wood. 

Living things, plants and animals when they die are the source of organic compounds. Ultimately, all the carbon in plants comes from the carbon dioxide in the air. 

At the high pressure of CO2 in the unopened can, the gaseous CO2 is in equilibrium with the dissolved gas. Therefore, the solution is saturated. When the bottle is opened and the pressure is released, the solubility decreases, and CO2 bubbles escape. Finally, the dissolved CO2 comes to equilibrium with the carbon dioxide in the air. The solution is saturated, but at this lower pressure, it is at a much lower concentration. 

If you collect rainwater in a relatively unpolluted area, you will discover that the rainwater is essentially a nonconductor of electricity. A small concentration of carbonic acid from the carbon dioxide in the air added to the rainwater causes the rain water to be a weak conductor. Pure rainwater conducts almost as poorly as distilled water. However, most of the water we use comes from wells, lakes, or rivers. This water has been in contact with soil and rocks, which contain ionic compounds that dissolve in the water. Consequently, tap water conducts electricity. The conduction is not high, but the water can conduct enough current to stop a person s heart. So, for example, a person should not use an electrical appliance when in the bathtub or shower. 

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